Workgroup Manager since 10.7 Lion no longer has an options to set any options for mail.
But they are still there. Even in 'Mountain Lion', 10.8.
Today I had to redirect a mail account of a user who left us to his successor.
In order to do so, you need the 'Directory Utility'. Is is located here
After starting the utility you have to go to LDAP and select the user. Then authenticate by clicking on the lock button using you OD admins account.
Now here's the trick.
The parameters regarding mail are located in the xml structure named 'MailAttribute'.
The two attributes that need to be changed are:
- kAutoForwardValue: from empty to the target email address
- kMailAccountState: from 'Enabled' to 'Forward'
That's all there is to it.
This may also be accomplished via command line using 'dscl'.
I found the infos I needed here.