I'm trying to migrate an old exchange 2000 to zimbra.
I'm using zimbra migration tool from zimbra homepage.
I've tried migrate just one account and apparently all the mails and folders were copied ok.

The only problem is that under exchange, the users email is something like:
firstname.lastname.mydomain.org but zimbra is creating email addresses like username@mydomain.org. The user alias are ok (first.last) but when I try to send a new email, the address in the "from field" is username@mydomain.org and not firsname.lastname.mydomain.org. How to I change this?