--- associations.rb.orig	2008-04-16 08:35:52.000000000 -0400
+++ associations.rb	2008-04-16 08:36:15.000000000 -0400
@@ -1544,7 +1544,7 @@
 
         def create_extension_modules(association_id, block_extension, extensions)
           if block_extension
-            extension_module_name = "#{self.to_s}#{association_id.to_s.camelize}AssociationExtension"
+            extension_module_name = "#{self.to_s.gsub(':', '')}#{association_id.to_s.camelize}AssociationExtension"
 
             silence_warnings do
               Object.const_set(extension_module_name, Module.new(&block_extension))