When it comes time to put in your email address... mis-spell 'gmail'... for example...
arparent@gSnail.com, The autosetup won't know its a gmail account, and it will let you set it up manually. Then, go back and change it back to 'gmail.' If you go to gmail.com, and check out the help/faq section, it gives instructions for setting up IMAP in Windows Mobile 6.