We use custom scripts to create quiesced snapshots, rather than snapmanager, and then dump to networker via NDMP.
It's all fairly straight forward. The saveset should reference the latest snapshot: /vol/somevol/.snapshot/dbbackup.new (or whatever your snaps are called).
The filer needs a backup user and password on it. This needs to be filled in in the networker client. The backup command needs to be filled in as something like: nsrndmp_save -P networker_server -M -T dump (with the appropriate networker server substituted). You also need the NDMP box ticked and the appropriate options in application information.