Now you can do clicks_button 'foo_123' (passing button ID, not value)

lib/webrat/field.rb

@@ -106,6 +106,10 @@ module Webrat
       @element["value"] =~ /^\W*#{Regexp.escape(value.to_s)}/i
     end
     
+    def matches_id?(id)
+      @element["id"] =~ /^\W*#{Regexp.escape(id.to_s)}/i
+    end
+    
     def matches_caption?(value)
       @element.innerHTML =~ /^\W*#{Regexp.escape(value.to_s)}/i
     end

lib/webrat/form.rb

@@ -33,6 +33,10 @@ module Webrat
       
       possible_buttons = fields_by_type([ButtonField])
       
+      possible_buttons.each do |possible_button|
+        return possible_button if possible_button.matches_id?(value)
+      end
+      
       possible_buttons.each do |possible_button|
         return possible_button if possible_button.matches_value?(value)
       end