polymorphic_url with link_to_remote

Hi.

I want to user the following link_to_remote with a polymporphic_url.

<%= link_to_remote "delete", :url => blog_entry_photo_path(entry, photo),:confirm => "Are your sure?", :method => :delete %>

This generates a not working link, without the photo_id. <%= link_to_remote 'delete', polymorphic_url([entry, photo], {:format => 'js'}), :confirm => 'Are you sure?', :method => :delete %>

Can anyone help me.

Thanks Michael