Listing 'rake routes' for a mountable Rails 3.1 engine

Question

I'm working on a mountable engine for use with Rails 3.1, and I want to list the engine's routes.

I created the engine using:

$ rails plugin new rails_blog_engine --mountable

And edited the 'test/dummy/config/routes' file to read:

Rails.application.routes.draw do
  mount RailsBlogEngine::Engine => "/blog"
end

...and 'config/routes' to read:

RailsBlogEngine::Engine.routes.draw do
  resources :posts
end

I want to list the routes generated for ':posts', but it's not clear how I can do this. When I run 'rake app:routes', I get only the "/blog" route:

$ rake app:routes
rails_blog_engine    /blog    {:to=>RailsBlogEngine::Engine}

When I run 'rake routes', I get an error:

$ rake routes
rake aborted!
Don't know how to build task 'routes'

How can I see the routes for ':posts'? Can I do this without rewriting the relevant rake tasks?