problems with 3 deep restful nesting

I have a

:user has_many :events has_many :signups

map.resources :users do |user|
    user.resources :events do |event|
      event.resources :signups
    end
  end

But in the 3rd nested resource im having trouble with the form_for( )
function.
The link to the page where the form lies works and i linked to it
with: new_user_event_signup_path(@user, @event) but the page
doesnt render with anything i have tried, and i have tried....!

so far ive tried:

form_for([@user, @signup])
form_for([@user, @event])
form_for([@event, @signup])

and everything in between...

oh, and i have tried all variations of 3 instances aswell... such as
form_for([@user, @event, @signup])

3 levels deep nesting is not nessessary, as the event as parent to the
signup is enough to keep a unique scope on the signup object.

1) use these routes:

map.resources :users do |user|
  user.resources :events
end
map.resources :events do |event|
   event.resources :signups
end

2) and this form defintion:
form_for([@event, @signup])

and everything is fine.

Also, you might want to check Jamis Buck's post on why 3 deep nested
resources may not be a good practice.

http://weblog.jamisbuck.org/2007/2/5/nesting-resources

Thanks! It workus!