Well, I would have upgraded to Netware 6.5, set up the users in NDS
utilized Mercury NLM's and Shoehorned Squirrel Mail on top using the
native Apache/PHP web services. That way you get total ease of user
administration, webmail access, rock solid reliability and reduced
exposure to cracks and viruses....but, I 'spose you can do it on W2k.
Read the documentation for M32 carefully.
I don't think Merc32 makes use of AD other than perhaps through LDAP.