We are starting the migration process, using the Zimbra Migration Wizard, moving mailboxes from Exchange 2000 to ZCS 5.0.11_GA. I've run into an issue with interoperability between the two systems from an addressing standpoint.

Once a user's mailbox is migrated to Zimbra and we've deleted their mailbox within Exchange, they no longer show up in the Exchange GAL, so our users who are still on Exchange cannot find them in the Address Book (GAL) to send them mail. What's the best solution to this? Do we have to create Exchange "Contacts" for all users who have moved onto ZCS, or is there a better way?