Rails3 routes

I'm migrating my app from Rails 2.3.8 to Rails 3.0.0 . But I've
problems in converting my routes.rb which looks like this:

ActionController::Routing::Routes.draw do |map|

  map.namespace(:admin) do |admin|
    admin.resources :participants
    admin.resources :communities, :has_many => :participants
    admin.resources :organizations
  end

  map.resources :memberships, :only => [:index]

  begin
    RessourceData.all.each do |r|
      map.resources r.ressource.to_sym, :path_prefix =>
'/'+r.namespace,
      :name_prefix => r.namespace+'_', :controller => 'messages',
      :only => [:index, :show, :create, :update, :destroy],
      :collection => { :fifo => [:get, :post], :lifo =>
[:get, :post] }
    end
  rescue ActiveRecord::StatementInvalid
    Rails.logger.info "DB error: #{$!}"
  end

end

With this code I'm able to do dynamic routing: the dynamic routes
where build out of the RessourceData model.
I've tried to convert these routes into Rails3 routes like this:

Ecs2::Application.routes.draw do

  namespace :admin do
    resources :participants
    resources :communities, :has_many => :participants
    resources :organizations
    resources :ressources
  end
  resources :memberships, :only => [:index]

  begin
    RessourceData.all.each do |r|
      namespace r.namespace.to_sym do
        resources r.ressource.to_sym, :controller => 'messages', :only
=> [:index, :show, :create, :update, :destroy] do
          collection do
            get 'fifo'
            post 'fifo'
            get 'lifo'
            post 'lifo'
          end
        end
      end
    end
  rescue ActiveRecord::StatementInvalid
    Rails.logger.info "DB error: #{$!}"
  end

But generated routes out of the RessourceData model aren't correct,
because the responsible controller is generated like "r.namespace/
r.ressource" instead of just "messages", e.g.

   "vip/exercises" instead of simply "messages"

Any suggestions ?