Johan,

Without sounding terribly trite, get another tape unit.

Single drive ADSM configurations, while workable from a technical standpoint, 
are an enormous pain in the neck.

That said, you will configure ADSM normally with one caveat: create a reclain 
storage pool area to allow for tape reclamation.

Kelly J. Lipp
Storage Solutions Specialists, Inc.
www.storsol.com
lipp AT storsol DOT com
(719)531-5926