How to Recover a mailbox when User Account is Deleted

The Recovery Storage Group in Exchange is great. It allows you to recover a mail store while leaving production mailboxes online. You can then ExMerge data from the RSG to PST. Problem: If the user account is missing then a ExMerge returns an error for that mailbox and doesn't present it in the GUI.

The error is: Error! Cannot identify the user with the msExchMailboxGuid \FE\40\D1\9C\DEOEA\A2\9C\A2\2E\7FHkx. The legacyExchangeDN is /O=RHD/OU=FIRST ADMINISTRATIVE GROUP/CN=RECIPIENTS/CN=JDOE.

Microsoft's KB919088 gives a workaround. I found I needed to add a step.

Essentially what you do is:

1. Recover from tape to the RSG normally, then dismount the RSG.
2. Create a new Storage Group
3. Create a new store, don't mount it.
4. Copy the EDB & STM files to the new stores database folder.
5. Rename the EDB & STM files to match the filename the new store is looking for.
5.5 Here's the extra step, go into properties of the store and set it to allow database to be overwritten by a restore.
6. Mount the store.
7. Create a new account, without a mailbox.
8. Attach the mailbox to be restored to the new account
9. Move the mailbox to a production store. Not sure why this step is necessary but it seems to be. I can never get ExMerge to read this new store. It may be due to replication delay. I'm not sure. The KB says to do this.
10. ExMerge the new account's mailbox normally. Note: the original legacyExchangeDN is preserved so the you need to find the account using the original user name.