On the type of hardware you are using to encrypt your data.  Is this a separate standalone solution from say, SUN?  If that is the case you may need to contact the hardware encryptor's vendor, because it may depend on the hardware as to the way you enable your drives for encryption.  I know with our solution, we have to have a license for x amount of keys, and each drive takes up a key.

 You will also need a Key management software. Netbackup KMS is an option

Check this: https://www-secure.symantec.com/connect/videos/encryption-options-netbackup