Unshortcutting archived messages to different Exchange Organization

My company is in process of migratting 7 AD forest into one new AD forest.  We are using the Quest tools to migrate users and mailboxes to the new forest.  one of the forest i am migrating has emailxtender installed and i have a large amount of archived mail.  is it possible to have emailxtender unshortcut the messages to the new exchange organization that will have the migrated mailboxes now.  on the exchange org which has emailxtender i dont have enough storage to unshortcut the messages.

Thanks

Richard