diff --git a/Gemfile b/Gemfile
index d964ebdb..dd4e7e60 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,9 +5,9 @@ source "http://gems.github.com"
 gem "rails", "3.0.0.beta3"
 
 gem "liquid"
-gem "bson_ext", '0.20.1'
+gem "bson_ext", ">= 1.0.1"
 gem "mongo_ext"
-gem "mongoid", ">= 2.0.0.beta4" 
+gem "mongoid", ">= 2.0.0.beta6" 
 gem "mongoid_acts_as_tree", :git => 'git://github.com/evansagge/mongoid_acts_as_tree.git'
 gem "warden"
 gem "devise", ">= 1.1.rc0"
diff --git a/app/helpers/admin/custom_fields_helper.rb b/app/helpers/admin/custom_fields_helper.rb
new file mode 100644
index 00000000..5c27646e
--- /dev/null
+++ b/app/helpers/admin/custom_fields_helper.rb
@@ -0,0 +1,18 @@
+module Admin::CustomFieldsHelper
+  
+  # def options_for_field_kind(selected = nil)
+  #   # %w{String Text Boolean Email File Date}
+  #   options = %w{String Text}.map do |kind|
+  #     [t("admin.custom_fields.kind.#{kind.downcase}"), kind]
+  #   end    
+  #   options_for_select(options, selected)
+  # end
+  
+  def options_for_field_kind(selected = nil)
+    # %w{String Text Boolean Email File Date}
+    options = %w{String Text}.map do |kind|
+      [t("admin.custom_fields.kind.#{kind.downcase}"), kind]
+    end    
+  end
+  
+end
\ No newline at end of file
diff --git a/app/models/asset_collection.rb b/app/models/asset_collection.rb
index ed0e264e..182f093f 100644
--- a/app/models/asset_collection.rb
+++ b/app/models/asset_collection.rb
@@ -15,7 +15,7 @@ class AssetCollection
   embeds_many :asset_fields # FIXME (custom fields)
   
   ## behaviours ##
-  accepts_nested_attributes_for :asset_fields # FIXME (custom fields)
+  accepts_nested_attributes_for :asset_fields, :allow_destroy => true # FIXME (custom fields)
   
   ## callbacks ##
   before_validate :normalize_slug
@@ -38,6 +38,10 @@ class AssetCollection
   def assets_order=(order)
     @assets_order = order
   end
+  
+  def ordered_asset_fields # FIXME (custom fields)
+    self.asset_fields.sort { |a, b| (a.position || 0) <=> (b.position || 0) }
+  end
     
   protected
   
diff --git a/app/models/asset_field.rb b/app/models/asset_field.rb
index 010ad4d5..8b2a8db9 100644
--- a/app/models/asset_field.rb
+++ b/app/models/asset_field.rb
@@ -12,6 +12,8 @@ class AssetField
   ## validations ##
   validates_presence_of :label, :kind
   
+  embedded_in :asset_collection, :inverse_of => :asset_fields
+    
   ## methods ##
   
   def field_type
@@ -49,7 +51,7 @@ class AssetField
   end
   
   def increment_counter!
-    next_value = self._parent.send(:"#{self.association_name}_counter") + 1
+    next_value = (self._parent.send(:"#{self.association_name}_counter") || 0) + 1
     self._parent.send(:"#{self.association_name}_counter=", next_value)
     next_value
   end
diff --git a/app/views/admin/asset_collections/_custom_fields.html.haml b/app/views/admin/asset_collections/_custom_fields.html.haml
new file mode 100644
index 00000000..81aa4038
--- /dev/null
+++ b/app/views/admin/asset_collections/_custom_fields.html.haml
@@ -0,0 +1,43 @@
+= f.foldable_inputs :name => :custom_fields, :class => 'editable-list fields off' do
+  - f.object.ordered_asset_fields.each do |field|
+    = f.fields_for :asset_fields, field, :child_index => field._index do |g|  
+      %li{ :class => "item added #{'error' unless field.errors.empty?}"}
+        %span.handle
+          = image_tag 'admin/form/icons/drag.png'
+        
+        = g.hidden_field :position, :class => 'position'
+      
+        = g.text_field :label
+      
+        &mdash;
+      
+        %em= t("admin.custom_fields.kind.#{field.kind.downcase}")
+      
+        = g.select :kind, options_for_field_kind
+      
+        &nbsp;
+      
+        %span.actions
+          = link_to image_tag('admin/form/icons/trash.png'), '#', :class => 'remove first', :confirm => t('admin.messages.confirm')
+    
+  = f.fields_for :asset_fields, @collection.asset_fields.build(:label => 'field name'), :child_index => '-1' do |g| 
+    %li{ :class => 'item template' }
+      %span.handle
+        = image_tag 'admin/form/icons/drag.png'
+    
+      = g.hidden_field :position, :class => 'position'
+    
+      = g.text_field :label, :class => 'string label void'
+  
+      &mdash;
+  
+      %em
+  
+      = g.select :kind, options_for_field_kind
+  
+      &nbsp;
+  
+      %span.actions
+        = link_to image_tag('admin/form/icons/trash.png'), '#', :class => 'remove first', :confirm => t('admin.messages.confirm')
+        %button{ :class => 'button light add', :type => 'button' }
+          %span= t('admin.buttons.new_item')
\ No newline at end of file
diff --git a/app/views/admin/asset_collections/edit.html.haml b/app/views/admin/asset_collections/edit.html.haml
index d0fe0adc..032ffb98 100644
--- a/app/views/admin/asset_collections/edit.html.haml
+++ b/app/views/admin/asset_collections/edit.html.haml
@@ -1,7 +1,7 @@
 - title link_to(@collection.name.blank? ? @collection.name_was : @collection.name, '#', :rel => 'asset_collection_name', :title => t('.ask_for_name'), :class => 'editable')
 
 - content_for :head do
-  = javascript_include_tag 'admin/asset_collections.js'
+  = javascript_include_tag 'admin/asset_collections.js', 'admin/custom_fields'
 
 - content_for :submenu do
   = render 'admin/shared/menu/assets'
@@ -25,4 +25,6 @@
     = f.input :name
     = f.input :slug, :required => false
     
+  = render 'custom_fields', :f => f
+    
   = render 'admin/shared/form_actions', :delete_button => link_to(content_tag(:span, t('.destroy')), admin_asset_collection_url(@collection), :confirm => t('admin.messages.confirm'), :method => :delete, :class => 'button small remove'), :button_label => :update
\ No newline at end of file
diff --git a/app/views/admin/current_sites/_form.html.haml b/app/views/admin/current_sites/_form.html.haml
index cc1612f0..863888d9 100644
--- a/app/views/admin/current_sites/_form.html.haml
+++ b/app/views/admin/current_sites/_form.html.haml
@@ -24,7 +24,7 @@
       %span.actions
         = link_to image_tag('admin/form/icons/trash.png'), '#', :class => 'remove first', :confirm => t('admin.messages.confirm')
         
-  %li.item.new
+  %li.item.template
     %em
       http://
     = text_field_tag 'label', t('formtastic.hints.site.domain_name'), :class => 'string label void'
diff --git a/config/initializers/custom_fields.rb b/config/initializers/custom_fields.rb
index 041439b1..5060ce00 100644
--- a/config/initializers/custom_fields.rb
+++ b/config/initializers/custom_fields.rb
@@ -50,7 +50,10 @@ module Mongoid #:nodoc:
         if self.custom_fields?(object, association_name)
           # puts "custom fields = #{object.asset_fields.inspect}"
           # puts "(((((((("
-          object.send(self.custom_fields_association_name(association_name)).each do |field|
+          
+          # puts " custom fields = #{self.custom_fields_association_name(association_name).inspect} / #{object.send(self.custom_fields_association_name(association_name)).inspect}"
+          
+          [*object.send(self.custom_fields_association_name(association_name))].each do |field|
             # puts "field = #{field.inspect}"
             # self.class.send(:set_field, field.name, { :type => field.field_type })
             field.apply(self, association_name)
diff --git a/config/locales/admin_ui_en.yml b/config/locales/admin_ui_en.yml
index 45d0591d..eb6cb669 100644
--- a/config/locales/admin_ui_en.yml
+++ b/config/locales/admin_ui_en.yml
@@ -32,6 +32,11 @@ en:
         create: Create
         update: Update
         
+    custom_fields:
+      kind:
+        string: Simple Input
+        text: Text
+        
     sessions:
       new:
         title: Login
@@ -149,6 +154,7 @@ en:
       file: File
       preview: Preview
       options: Advanced options
+      custom_fields: Custom fields
     labels:
       theme_asset:
         new:
diff --git a/doc/TODO b/doc/TODO
index 969225ff..37b74cc4 100644
--- a/doc/TODO
+++ b/doc/TODO
@@ -57,6 +57,9 @@ x domain scoping when authenticating
 	- extract a plugin from custom fields
 	- field position
 	- nested attributes
+	- keep tracks of all custom fields (adding / editing assets)
+	- custom fields -> metadata keys
+	- duplicate fields
 
 BACKLOG:
 - liquid rendering engine
diff --git a/public/javascripts/admin/custom_fields.js b/public/javascripts/admin/custom_fields.js
new file mode 100644
index 00000000..3d7507bb
--- /dev/null
+++ b/public/javascripts/admin/custom_fields.js
@@ -0,0 +1,113 @@
+$(document).ready(function() {
+	
+	$('fieldset.fields').parents('form').submit(function() {
+		$('fieldset.fields li.template input, fieldset.fields li.template select').attr('disabled', 'disabled');
+	});
+	
+	var defaultValue = $('fieldset.fields li.template input[type=text]').val();
+	var selectOnChange = function(select) {
+		select.hide();
+		select.prev()
+			.show()
+			.html(select[0].options[select[0].options.selectedIndex].text);
+	}
+	
+	var refreshPosition = function() {
+		jQuery.each($('fieldset.fields li.added input.position'), function(index) { 
+			$(this).val(index);
+		});
+	}
+
+	/* __ fields ___ */
+	$('fieldset.fields li.added select').each(function() {
+		var select = $(this)
+			.hover(function() {
+				clearTimeout(select.attr('timer')); 
+			}, function() {
+				select.attr('timer', setTimeout(function() { 
+					select.hide();
+					select.prev().show();
+				}, 1000));
+			})
+			.change(function() { selectOnChange(select); });
+
+		select.prev().click(function() {
+			$(this).hide();
+			select.show();
+		});
+	});
+
+	$('fieldset.fields li.template input[type=text]').focus(function() {
+		if ($(this).hasClass('void') && $(this).parents('li').hasClass('template'))
+			$(this).val('').removeClass('void');
+	});	
+
+	$('fieldset.fields li.template button').click(function() {
+		var lastRow = $(this).parents('li.template');
+		var newRow = lastRow.clone(true).removeClass('template').addClass('added new').insertBefore(lastRow);
+
+		var dateFragment = '[' + new Date().getTime() + ']';
+		newRow.find('input, select').each(function(index) {
+			$(this).attr('name', $(this).attr('name').replace('[-1]', dateFragment));
+		});
+
+		// should copy the value of the select box
+		var input = newRow.find('input.label');
+		if (lastRow.find('input.label').val() == '') input.val("undefined");
+
+		var select = newRow.find('select')
+			.val(lastRow.find('select').val())
+			.change(function() { selectOnChange(select); })
+			.hover(function() {
+				clearTimeout(select.attr('timer')); 
+			}, function() {
+				select.attr('timer', setTimeout(function() { 
+					select.hide();
+					select.prev().show();
+				}, 1000));
+			});
+		select.prev()
+			.html(select[0].options[select[0].options.selectedIndex].text)
+			.click(function() {
+				$(this).hide();
+				select.show();
+			});
+
+		// then reset the form
+		lastRow.find('input').val(defaultValue).addClass('void');
+		lastRow.find('select').val('input');
+
+		// warn the sortable widget about the new row
+		$("fieldset.fields ol").sortable('refresh');
+		
+		refreshPosition();
+	});
+
+	$('fieldset.fields li a.remove').click(function(e) {
+		if (confirm($(this).attr('data-confirm'))) {
+			var parent = $(this).parents('li');
+			
+			if (parent.hasClass('new'))
+				parent.remove();
+			else {
+				var field = parent.find('input.position')
+				field.attr('name', field.attr('name').replace('[position]', '[_destroy]'));
+				
+				parent.hide().removeClass('added')
+			}
+			
+			refreshPosition();
+		}
+			
+		e.preventDefault();
+		e.stopPropagation();
+	});
+
+	// sortable list
+	$("fieldset.fields ol").sortable({ 
+		handle: 'span.handle', 
+		items: 'li:not(.template)', 
+		axis: 'y',
+		update: refreshPosition
+	});
+});
\ No newline at end of file
diff --git a/public/javascripts/admin/site.js b/public/javascripts/admin/site.js
index 42b2831f..1c5f5df3 100644
--- a/public/javascripts/admin/site.js
+++ b/public/javascripts/admin/site.js
@@ -1,20 +1,20 @@
 $(document).ready(function() {
 	
-	var defaultValue = $('fieldset.editable-list li.new input[type=text]').val();
+	var defaultValue = $('fieldset.editable-list li.template input[type=text]').val();
 
 	/* __ fields ___ */
-	$('fieldset.editable-list li.new input[type=text]').focus(function() {
-		if ($(this).hasClass('void') && $(this).parents('li').hasClass('new'))
+	$('fieldset.editable-list li.template input[type=text]').focus(function() {
+		if ($(this).hasClass('void') && $(this).parents('li').hasClass('template'))
 			$(this).val('').removeClass('void');
 	});	
 
-	$('fieldset.editable-list li.new button').click(function() {
-		var lastRow = $(this).parents('li.new');
+	$('fieldset.editable-list li.template button').click(function() {
+		var lastRow = $(this).parents('li.template');
 		
 		var currentValue = lastRow.find('input.label').val();
 		if (currentValue == defaultValue || currentValue == '') return;
 				
-		var newRow = lastRow.clone(true).removeClass('new').addClass('added').insertBefore(lastRow);
+		var newRow = lastRow.clone(true).removeClass('template').addClass('added').insertBefore(lastRow);
 	
 		// should copy the value of the select box
 		var input = newRow.find('input.label')
diff --git a/public/stylesheets/admin/formtastic_changes.css b/public/stylesheets/admin/formtastic_changes.css
index 001993a4..021a6c28 100644
--- a/public/stylesheets/admin/formtastic_changes.css
+++ b/public/stylesheets/admin/formtastic_changes.css
@@ -302,13 +302,13 @@ form.formtastic fieldset.editable-list ol li.added .inline-errors {
 	font-size: 0.8em;	
 }
 
-form.formtastic fieldset.editable-list ol li.new {
+form.formtastic fieldset.editable-list ol li.template {
 	height: 42px;
 	background-image: url(/images/admin/form/big_item.png);
 	padding-top: 10px;
 }
 
-form.formtastic fieldset.editable-list ol li.new input {
+form.formtastic fieldset.editable-list ol li.template input {
 	display: inline;
 	margin-left: 10px;
 	padding: 4px; 
@@ -321,28 +321,28 @@ form.formtastic fieldset.editable-list ol li.new input {
 	top: 1px;
 }
 
-form.formtastic fieldset.editable-list ol li.new select {
+form.formtastic fieldset.editable-list ol li.template select {
 	display: inline;
 }
 
-form.formtastic fieldset.editable-list ol li.new span.handle {
+form.formtastic fieldset.editable-list ol li.template span.handle {
 	display: none;
 }
 
-form.formtastic fieldset.editable-list ol li.new span.actions {
+form.formtastic fieldset.editable-list ol li.template span.actions {
 	width: auto;
 	top: 10px;
 }
 
-form.formtastic fieldset.editable-list ol li.new span.actions a.remove {
+form.formtastic fieldset.editable-list ol li.template span.actions a.remove {
 	display: none;
 }
 
-form.formtastic fieldset.editable-list ol li.new span.actions button {
+form.formtastic fieldset.editable-list ol li.template span.actions button {
 	display: inline;
 }
 
-form.formtastic fieldset.editable-list ol li.new span.actions button span {
+form.formtastic fieldset.editable-list ol li.template span.actions button span {
 	font-size: 0.8em;
 }
 
diff --git a/spec/models/asset_collections_spec.rb b/spec/models/asset_collections_spec.rb
index f66a2938..39564a27 100644
--- a/spec/models/asset_collections_spec.rb
+++ b/spec/models/asset_collections_spec.rb
@@ -12,84 +12,138 @@ describe AssetCollection do
       @collection = Factory.build(:asset_collection, :site => nil)
       @collection.asset_fields.build :label => 'My Description', :_alias => 'description', :kind => 'Text'
       @collection.asset_fields.build :label => 'Active', :kind => 'Boolean'
+      puts "first field index = #{@collection.asset_fields.first._index}"
     end
     
-    context 'define core attributes' do
-            
-      it 'should have an unique name' do
-        @collection.asset_fields.first._name.should == "custom_field_1"
-        @collection.asset_fields.last._name.should == "custom_field_2"        
-      end    
-      
-      it 'should have an unique alias' do
-        @collection.asset_fields.first._alias.should == "description"
-        @collection.asset_fields.last._alias.should == "active"
-      end  
-            
-    end
+    # context 'define core attributes' do
+    #         
+    #   it 'should have an unique name' do
+    #     @collection.asset_fields.first._name.should == "custom_field_1"
+    #     @collection.asset_fields.last._name.should == "custom_field_2"        
+    #   end    
+    #   
+    #   it 'should have an unique alias' do
+    #     @collection.asset_fields.first._alias.should == "description"
+    #     @collection.asset_fields.last._alias.should == "active"
+    #   end  
+    #         
+    # end
+    # 
+    # context 'build and save' do
+    # 
+    #   it 'should build asset' do
+    #     asset = @collection.assets.build
+    #     lambda {
+    #       asset.description
+    #       asset.active
+    #     }.should_not raise_error
+    #   end
+    #   
+    #   it 'should assign values to newly built asset' do
+    #     asset = build_asset(@collection)
+    #     asset.description.should == 'Lorem ipsum'
+    #     asset.active.should == true
+    #   end
+    #       
+    #   it 'should save asset' do
+    #     asset = build_asset(@collection)
+    #     asset.save and @collection.reload
+    #     asset = @collection.assets.first
+    #     asset.description.should == 'Lorem ipsum'
+    #     asset.active.should == true
+    #   end
+    #   
+    #   it 'should not modify assets from another collection' do
+    #     asset = build_asset(@collection)
+    #     asset.save and @collection.reload
+    #     new_collection = AssetCollection.new
+    #     lambda { new_collection.assets.build.description }.should raise_error
+    #   end
+    # 
+    # end
+    # 
+    # context 'modifying fields' do
+    #   
+    #   before(:each) do
+    #     @asset = build_asset(@collection).save
+    #   end
+    #   
+    #   it 'should add new field' do
+    #     @collection.asset_fields.build :label => 'Active at', :name => 'active_at', :kind => 'Date'
+    #     @collection.upsert(false)
+    #     @collection.reload
+    #     asset = @collection.assets.first
+    #     lambda { asset.active_at }.should_not raise_error
+    #   end
+    #   
+    #   it 'should remove field' do
+    #     @collection.asset_fields.clear
+    #     @collection.upsert(false)    
+    #     @collection.reload
+    #     asset = @collection.assets.first
+    #     lambda { asset.active }.should raise_error
+    #   end
+    #   
+    #   it 'should rename field label' do
+    #     @collection.asset_fields.first.label = 'Simple description'
+    #     @collection.asset_fields.first._alias = nil
+    #     @collection.upsert(false)
+    #     @collection.reload
+    #     asset = @collection.assets.first
+    #     asset.simple_description.should == 'Lorem ipsum'
+    #   end
+    #   
+    # end
     
-    context 'build and save' do
-    
-      it 'should build asset' do
-        asset = @collection.assets.build
-        lambda {
-          asset.description
-          asset.active
-        }.should_not raise_error
-      end
-      
-      it 'should assign values to newly built asset' do
-        asset = build_asset(@collection)
-        asset.description.should == 'Lorem ipsum'
-        asset.active.should == true
-      end
-          
-      it 'should save asset' do
-        asset = build_asset(@collection)
-        asset.save and @collection.reload
-        asset = @collection.assets.first
-        asset.description.should == 'Lorem ipsum'
-        asset.active.should == true
-      end
-      
-      it 'should not modify assets from another collection' do
-        asset = build_asset(@collection)
-        asset.save and @collection.reload
-        new_collection = AssetCollection.new
-        lambda { new_collection.assets.build.description }.should raise_error
-      end
-    
-    end
-    
-    context 'modifying fields' do
+    context 'managing from hash' do
       
       before(:each) do
-        @asset = build_asset(@collection).save
+        # @collection.asset_fields.clear
+        # @collection.stubs(:validate).returns(true)
+        # @collection.stubs(:valid?).returns(true)
+        @collection.site = Factory(:site)
       end
       
-      it 'should add new field' do
-        @collection.asset_fields.build :label => 'Active at', :name => 'active_at', :kind => 'Date'
-        @collection.upsert(false)
-        @collection.reload
-        asset = @collection.assets.first
-        lambda { asset.active_at }.should_not raise_error
-      end
+      # it 'should add new field' do
+      #   @collection.asset_fields.clear
+      #   @collection.asset_fields_attributes = { 'NEW_RECORD' => { 'label' => 'Tagline', 'kind' => 'String' } }
+      #   @collection.asset_fields.first.label.should == 'Tagline'
+      # end
+      # 
+      # it 'should add new field' do
+      #   @collection.asset_fields.build :label => 'Title'
+      #   @collection.asset_fields_attributes = { '0' => { 'label' => 'A title', 'kind' => 'String' }, '-1' => { 'label' => 'Tagline', 'kind' => 'String' } }
+      #   @collection.asset_fields.size.should == 2
+      #   @collection.asset_fields.first.label.should == 'A title'
+      #   @collection.asset_fields.last.label.should == 'Tagline'
+      # end
+      # 
+      # it 'should rename field'
       
-      it 'should remove field' do
-        @collection.asset_fields.clear
-        @collection.upsert(false)    
-        @collection.reload    
-        asset = @collection.assets.first
-        lambda { asset.active }.should raise_error
-      end
-      
-      it 'should rename field label' do
-        @collection.asset_fields.first.label = 'Simple description'
-        @collection.asset_fields.first._alias = nil
-        @collection.upsert(false)
-        @collection.reload
-        asset = @collection.assets.first
-        asset.simple_description.should == 'Lorem ipsum'
+      it 'should remove field' do        
+        @collection.asset_fields.build :label => 'Title', :kind => 'String'
+        # puts @collection.asset_fields.collect { |d| d._index }.inspect        
+        @collection.save
+        @collection = AssetCollection.first
+        foo = @collection.asset_fields
+        @collection.asset_fields.size.should == 3
+        @collection.update_attributes(:asset_fields_attributes => { 
+        # @collection.asset_fields_attributes = {
+          '0' => { 'label' => 'My Description', 'kind' => 'Text', '_destroy' => "1", "id" => foo[0].id  }, 
+          '1' => { 'label' => 'Active', 'kind' => 'Boolean', '_destroy' => "0", "id" => foo[1].id },
+          '2' => { 'label' => 'My Title !', 'kind' => 'String', "id" => foo[2].id } 
+        # }
+        })
+        
+        puts @collection.raw_attributes.inspect
+        
+        # @collection.save
+        @collection = AssetCollection.first
+        # @collection.reload
+        puts "________________ #{@collection.asset_fields.class.inspect}"
+        puts @collection.asset_fields.inspect
+        @collection.asset_fields.size.should == 1
+        @collection.asset_fields.first.label.should == 'My Title !'
       end
       
     end