User required in Profile Manager Exchange settings
You can use %short_name% and %long_name% to autofill some fields (such as email address, username, full name) in Profile Manager, and they will pull that information from your user directory.
If you're using Google Apps via Exchange ActiveSync, then that will only work if your on demand user accounts have the same short name as your Google Apps user accounts, or if you are syncing the two together.