The Sun PROM expects the tape drives to have:
  st0:	target 4, LUN 0
  st1:	target 5, LUN 0
(At least, if I recall correctly:)

Try setting the SCSI target ID = 4.

The MT02 board has an 8 position switch block near J1.
Here is the description from the F.E. handbook:
SW	Factory		Description
 1	Off		Target ID bit zero
 2	Off		Target ID bit one
 3	On		Target ID bit two  (ID=4)
 4	Off		Not used
 5	On		drive type
 6	(*)		drive type: (* Archive: Off, Wangtek: On)
 7	Off		drive type
 8	Off		SCSI bus parity check