Encrypt OST Storage Device

I'd like to encrypt our Dell DR4100 deduplication device that we've been backing up to for a few years. I've read through the DR admin guide and the Backup Exec/DR4100 white paper:

https://support.quest.com/dr-series/dr4300/technical-documents?started=6079199

After I enable encryption and set the passphrase on the 4100, do I need to use the passphrase somewhere in BE? All I see in the white paper is that the encryption type in the job storage section should be set to None.

Does anyone have experience with a DR series device or some other encrypted storage device who can give me some guidance? The encryption process is irreversible, so I need to make sure I understand it before I enable it.

Thanks.