Directory-based email

I would like to know where I change the mail server for email account delivered to clients via OD. This is my scenario: OpenDirectory + file server ("directory.example.com") Mail server ("mail.example.com" Client All are using 10.6.3. When I set up a new client from the ground up the setup procedure allows me to enter the username and password of a user in the directory to setup email accounts automatically. It does that; I get a server in the Accounts tab in Mail->Preferences with a "user@directory.example.com". What I was expecting was "user@example.com". I can't find the property anywhere in Workgroup Manager (I suspsect it is denoted somewhere as "%@@%h" or similar) and rummaging through Apple's PDFs has resulted nothing. Even setting up an MCX property for that user doesn't work; there is no additional account created, even after restarting the machine. On a related note, setting up iCal accounts centrally like that would be great... Can anyone tell me where I should look?