[Zope] Folderish Product Problems

I am trying to create a Folderish Product that can be accessed via ftp/webdav. I have tried subclassing both (one at a time) ObjectManager and Collection, but when I open the folder in ZMI or ftp, it appears again, nested within itself-it will nest forever. Not sure why? Can someone please offer any advice on why it is doing that? I assume that I am missing a method that needs to be implemented? Thanks, Chris