Now do you have your environment set to require a backup prior to HSM
migrating data off to TSM ?
If you do and you have in fact lost the HSM data, then you may restore the
client's data from backups (and then migrate it off again)  long process but
works.
All HSM data here has to have a valid backup prior to migration since TSM
will be keeping the only valid copies of the data.

Now for the tape volume...
have you tried a "move data" ?
I don't know if that would get you past the label problem or not...
also an audit volume on it might be worth a try...

For a price, IBM can pull data off a destroyed tape.

Dwight