[Zope] Which LDAP product?

I've been looking for a Zope product that makes Zope LDAP enabled. However I really dont know which one to choose? Or, should I have to write my own LDAP adaptor? If anyone has experience on using Zope with LDAP, please kindly give me some suggestions. Thanks :) BTW, has anyone ever tried running Zope on AIX? Any experience to share? Thanks :) -- Nick