[Zope] URLSessionAdapter and SiteRoot

Hi! I've a weird problem with the combination of an URLSessionAdapter and SiteRoot: In a folder with an URLSessionAdapter I can't use the management Interface, since there seems to be a 'rewriting loop' with news sessions, ending in an 'URL to long error' To illustrate the problem a snippet from the URL from apaches logfile: /NLAAdmin/NLAOverview/48655453A0WSQ3E4dzs/pt_editForm/NLAOverview/09137742A0WSQ3HmyLM/NLAAdmin/NLAOverview/pt_editForm/ ...... What's going wrong here and how can I fix this?