If this has been sent to the list already, my apologies.

Seems APAR IC28573 covers the problem with the volhist not being deleted
after a successful delete of a backupset according to Tivoli support.
This, as many know, causes the library volume that the backupset was on to
be not available to the scratch pool and can only be private.  This APAR
covers both 3.7 and 4.1.  It is not mentioned as a fix under 4.2, so if it
was addressed under 4.2, I do not know as of now.  I am waiting on Tivoli
to get back to me on the time-frame as when a fix will be released and
weather it is an issue under 4.2.  I hope this helps.

 -> Mark