[Zope] UserLDAP and HTTP Authentication

Hi everyone, I've just installed Zope 2.1.4 with UserLDAP and was able to connect to the LDAP server fine and get my list of users. Now, what I wanted to do is have HTTP authentication based on a certain attribute like 'access' for example. How is this done? I'm new on Zope and still trying to learn python. I'd really appreciate any help. Thanks in advance, Mike