Non numeric IDs in member resources

I have a nested resource:

map.resources :posts do |posts|    posts.resources :comments end

which generates urls like:

posts/1/comments/2

Is there any way to use a "name" or other parameter instead of params[:id] for posts?. In other words I'd like to have a url like

posts/some-name-here/comments/2

Is something like resource_hacks my only hope?

-vega