EV Backup - NAS based Partitions/NDMP

Hello All-

We are running EV8, and have recently moved our EV partition from local storage to a NAS, with Netbackup as the backup solution.  Previously, the archive bit was being set by Netbackup and all was functioning swell - but since we've moved the data, the safety copies aren't being purged, as the NAS is being backed up via NDMP and has no mechanism to flip the archive bit.

I understand that a trigger file can be used, but I am unsure how/when that should be created.  Should that be a function of the NDMP job??  Would the Netbackup EV agent alleviate this??

Considering that we do pretty frequent snapshots (4x daily) on the NAS volumes, and daily backups to tape - are safety copies even necessary?

Thanks in advance!

roc