Depending upon your setup….
What is the DIR/MIR set to? It may be possible to recover the mail without going to tape.
If you are still within the DIR/MIR settings, simply change the pw on the account, enable the account, and then login as the user, create a profile for the mailbox.
Google “DumpsterAlwaysOn” and implement on the workstation.
Recover mail using Outlook.
I am a bit confused why you show an exmerge log when you said that you were mounting a Recovery Storage Group after restoring from BackupExec. “In Theory,” if you have the RSG with the mailbox in it, just move the mailbox over to an active storage group and connect it to the user object.