expire_action silently failing with :as routes

I am having problems with expiring action caches in Rails 2.2. I have a configured the route for a controller named Pages to appear as "pagine" using the :as option. I am using the file based cache and the caching works although the created files match the controller name (e.g. /pages/1). However when I try and expire the action it looks for a file that matches the name I gave rather than the controller name.

So rather than trying to delete /pages/1 it tries to delete /pagine/1 and so the action is never expired.