It may be a bit convoluted, but this is how I do it:
I have a Dell ML6020, but the setup should be the same as for the HP.
From BE, I created partitions on the library, one for each slot (be mindful of the 0 slot). I then created a backup job for each day (named Mon, Tues, etc) and assigned each job to a particular slot/partition. Tapes are overwritten each week.
On the first day of the month, I remove the tape that was backed up to the night before and use that as my permanent archive for the month.