format.atom w Rails 2.2

in Rails 2.1, this works.. but I am stuck w Rails 2.2

class PostsController < ApplicationController   def show      ......     respond_to do |format|       format.html       format.atom { render :action => 'changes', :layout => false, :content_type => 'application/atom+xml' }     end   end

  def changes      ........     respond_to do |format|       format.xml { render :layout => false, :content_type => 'application/atom+xml' }     end   end .. end

I have a view, changes.xml.builder, building the xml code, but I got a missing template as an error, when executing http://localhost:3000/posts/show/5

ActionView::MissingTemplate (Missing template posts/changes.erb in view path .../Projects/franchising/app/views:): If I set a changes.erb, the xml code is sent...

how should I write that w Rails 2.2 ?

thanks a lot for your help

erwin

mistaken.... shoudl write changes.rxml and not xml.builder !!! dawned copy/paste !!