Maybe these instructions from the gmail site can help. I use gmail from the TouchFlo screen without a problem. Then if you really want to get fancy, use Makisu XML or Shashimi to make setup easier after each ROM flash.
To configure IMAP for your Windows Mobile 6 device, just follow these steps:
1. Enable IMAP in your Gmail settings.
2. Open the Start menu and select Programs > Messaging > New E-mail Account.
3. Enter your Gmail address (including '@gmail.com') in the E-mail Address field*. Google Apps users, enter your full address in the format 'username@your_domain.com'*.
* Windows Mobile 6.1 users: Enter an unintelligible email address (such as 'g@g') at this step. This will bypass the automatic configuration for POP access.
4. Uncheck the box that asks to get settings automatically from the Internet and select Next.
5. Select Internet e-mail as your email provider in the drop-down menu.
6. Enter your name as you want it to appear in sent emails.
7. Enter a descriptive name for the email account and select Next.
8. Enter 'imap.gmail.com' in the Incoming Mail Server field.
9. Select IMAP4 as the Account type from the drop-down menu and select Next.
10. Enter your full email address (including '@gmail.com' or '@your_domain.com') and password.
11. Select Next.
12. Enter 'smtp.gmail.com' in the Outgoing (SMTP) Mail Server field.
13. Make sure that the Outgoing server requires authentication box is checked.
14. Select the Advanced Server Settings link.
15. Make sure that the Require SSL box is checked for both incoming and outgoing emails.
16. Select The Internet as the network connection from the drop-down menu.
17. Select Done and then Next.
18. Select how often you want your phone to send/receive emails from the drop-down menu.
19. For more download options, select the Review all download settings link.
20. Select Finish.
21. Check our recommended client settings, and adjust your client's settings as needed.
Sashimi/Makisu:
http://www.winmo-experts.com/