How do I have an encrypted NDMP backup to tapes?

Hi,
 
We have to take an encrypted NDMP tape backups from a NetApp filer connected via fiber to LTO 4 tape library. Backups jobs (schedules) should handle by Symantec Netbackup software.

My questions are about encrypting the data before the data goes on tape. 

1. Is encryption possible? If so, who controls the encryption keys?

2. What sort of licenses do we require in Symantec Netbackp?

3. Do we need to buy an encryption kit for our tape library?

4. Since the actual data path is through NetApp Filer to tape, does it really require to have encryption license in Symantec Netbackup?

5. What is the minimum version of NDMP & Netbackup supported?

6. How can this system be set up?

Many thanks