These setup instructions apply to Android versions 2.0 though 2.1.
Enter your email address and password then tap Manual Setup.
Select IMAP for the account type screen.
Enter your username (your email address without @xmission.com), and change the IMAP server to mail.xmission.com then tap next.
Change the SMTP server to: mail.xmission.com and make sure there is a check mark in Require sign-in. Then tap next.
From the account options settings select what frequency you wish to check for new email and if you want notifications when these messages arrive.
Name the account XMission and enter your name then tap done. Congratulations on your new mail account.