Zimbra expect to release a SLES10/SUSE10.1 version with the release of 4.0.2
As far as when in months/weeks this would be in the region of 6months I think - the Zimbra engineers would be best to speculate the time scale.
One thing I would add to your config is an alias for
root@server.fqdn as Zimbra will send out daily stats for the server. As you changed the default domain these messages will got to the root accounts mailbox, and not neccessarily the Mail Admin's account.
Nice tips though.