[Zope] Session manager without pickle?

Hi! I'd like to open and store a database connection per session to enable things like transactions over multiple http accesses, use of (existing) python code, user authorization via database server etc. Unfortunately the session manager tries to pickle the connection object, which of course doesn't work here. Is it possible to avoid this? Anyway, as session data should be stored in RAM, I don't see the point of pickling... If it's possible to do what I want, is it also possible/necessary to avoid multiple concurrent accesses from the same user/session? Regards, Dietmar