[Zope] LOGIN MECHANISM

[chpeer2002]

What I want to realise:
- web-application with zope user login
- username, password stored in an Interbase database
- session tracking

I've been searching for a while how to solve the login problem.

Could you give me an answer to the following questions?

1) Is it possible to use the normal acl_user folder together the 
Interbase database? (How??)

2) Situation with ZODB: given is a web-page where a user can decide 
on one of two web-apps. He than has to login (zope user) using a web 
form. When the user logs out and than clicks the "back" button of the 
browser a few times he comes back to the first page. When the user 
now decides on the other web-app he is automatically logged in 
because the username and password are the same for both apps.
I would like to force the user to login again. Do you have an idea? 

3) Which login mechanism is used at zope.org? (ZODB??)

Thanks for any help?
Christian