First thanks to J. Albrecht, Dave Hill & Alan Hamilton for getting me this
far:
------------------------------------------------------------------------------
adsm> define devc 3570class devt=3570 format=drive libr=3570libr mountr=5
adsm> define devc 3570class devt=3570 format=drive libr=3570libr mountr=5
mountl=2
ANR2203I Device class 3570CLASS defined.

adsm> define library 3570libr libtype=scsi device=/dev/rmt1.smc
ANR8400I Library 3570LIBR defined.

adsm> define drive 3570libr drive0 device=/dev/rmt1 element=16
ANR8404I Drive DRIVE0 defined in library 3570LIBR.

adsm> define drive 3570libr drive1 device=/dev/rmt2 element=17
ANR8404I Drive DRIVE1 defined in library 3570LIBR.

adsm> quit

ANS5103I Highest return code was 10.


$ dsmlabel -drive=/dev/rmt1 -library=/dev/rmt1.smc -search -keep

ADSTAR Distributed Storage Manager for AIX-RS/6000
Volume Label Utility Program
Version 2, Release 1, Level 0.13/5.13

Licensed Materials - Property of IBM

5765-203 (C) Copyright IBM Corporation 1994, 1996.  All rights reserved.
U.S. Government Users Restricted Rights - Use, duplication or disclosure
restricted by GSA ADP Schedule Contract with IBM Corporation.

ANR9739I Initializing library device '/dev/rmt1.smc'.
ANR9742E The element address for drive '/dev/rmt1' is missing or invalid.
$