I missed one important detail on the conversion for IMAP users:

Use your email address ([log in to unmask]) as your username when connecting 
to the server.


Jonathan Goldman                    Volgenau School of Engineering
Director of Computing Resources            George Mason University
(703) 993-3506                         4400 University Dr. MSN 4A3
fax  (703) 993-3977                         Fairfax, VA 22030-4444