TDP 2.2 doesn't backup individual mailbox. For each backup tool that perform
this kind of operation backup are very, very, very slow. It have to be used
only for VP mailboxes.
There is a tools that can perform extract of Exchange DB to one PST file per
mailbox. (Xmerge)
You can use this tools to backup some mailboxes. And then backup PST thru
TSM as flat file.

Regards,
Eric