I received the following process from Kodak for adding tapes to the pool for my AIT-3 tape system. I don't know if it will help or not but you may want to give it a shot.
Allocation/Deallocation policy: Select both Draw media from Free media pool and Return media to Free media pool.
· Prepare the tapes to be included in Backup media rotation.
· In NTBackup, configure a small New Media backup job. This configures NTBackup to grab a tape from the free pool.
· Click Start Backup.
· In the If the media is overwritten, use this label to identify the media box, type the tape name.
· Click Start Backup.
· After the backup is done, close NTBackup.
· Move the allocated tape into the Backup\Prinergy pool.
· Repeat this procedure to allocate the required number of backup tapes in the Backup\Prinergy pool, so Prinergy Backup can alternate using those tapes for backup