solaris should use the native st module (SCSI tape Driver), plug your cable in and run the "devfsadm -v" command. you should find a /dev/rmt/0 device now. to test it, you can use "mt status" or "tar" to backup something...

same way with your new drive, but we would need more information to guide you, post an "iostat -En" output after devfsadm....

gP