additional tape drives not detected correctly by Backup Exec Appliance 3600

Here's our setup:

Backup Exec Appliance 3600 with three HP SAS tape drives

Quantum Scalar i80

The first tape drive is connected via SAS cable to the BE Appliance.

Issue:

BE does not correctly detect tape drives 2 and 3. I've troubleshooted with both vendors, checked diagnostic logs, looked for alternate drivers, all without success.

Anyone got an idea what's going on? Any help would be appreciated.