Hi,
This is general NDMP info:
1) If you want to have dedicated tape library for NDMP backups for SAN via Fibre_channel:
a) zone the tape drive(s) FC port to NetApp
b) zone the Medium changer FC port (Robotic arm) to Backup/Media Server [In your case Archserv server]
c) Once zoning is in place, run Device detection from the Backup server, this will allow you to configure NDMP Pool for the tape drives as target for Backups. This will allow NAS data to flow from NAS to Tape Library via Fibre.
2) If want to have shared tape-library for both NDMP and Non-NAS (NDMP) data then you must look at the DDS option that comes with Arcserve.
Found a arcserve doc online, please take a look: [configure DDS page:30]
https://documentation.arcserve.com/Arcserve-Backup/Available/R16/ENU/Bookshelf_Files/PDF/AB_NDMP_NAS_W_ENU.pdf
It might be worth logging a call with Arcserve to get this setup.