If the library is designed to do it for you, you get a message from Backup Exec requesting that you put/take the tape in/out of the PORTAL.
If the library expects you to do it, you get a message from Backup Exec requesting that you put/take the tape in/out of the SLOT (either manually or via an interface)
Which message are you getting?
Another way to tell is to look in the adamm.log file where it documents what type you have. I expect you will see:
1st Slot Number 1
Number Of Slots 8
Portal Slots 0
Import/Export Manual