Barracuda 850 Archive backup methods?

Is anyone backing up a Barracuda 850 email archive appliance with Netbackup 7.5?  I cant seem to figure out a method to access the system to back it up and there documentation is providing no assistance.

Their method is to setup an SMB share on the Email appliance and then use 3rd party software to access the share and backup the files.

I've read about doing off host backups but the appliance share access is a local account on the appliance.  I can get to it from windows but Netbackup can resolve the local account.