Rails 3.0.5 initializer that monkeypatches in lieu of https://github.com/glv/rails/commit/93389371d17472023d4884643e755725dce9aa6d

fix_association_extensions.rb

require 'active_record'

module ActiveRecord
  module Associations

    # This fix allows the association extension methods to work when used in combination
    # with built-in Arel scoping methods (where, joins, etc.) and *also* with named scopes
    # defined on the target class.
    class AssociationProxy
      def with_scope_with_extensions(*args, &block)
        result = with_scope_without_extensions(*args, &block)
        return result unless Relation === result
        result.extending(*Array.wrap(@reflection.options[:extend]))
      end
      
      alias_method_chain :with_scope, :extensions
    end
  end
end