Crickets... We resolved this by going with Symantec Backup Exec NDMP. We specifically wanted to back up to a tape device that was connected directly to the backup server rather than to the NetApp. That apparently threw a kink into things. Backup Exec will allow you to do this, but will fail the authentication test. It will backup and restore files regardless.
The link mentioned by Radek is dead, as the ITRC was replaced by the HP Support Center. I have tried searching for the abovementioned thread and cannot locate it. Can someone either provide an updated link or possibly point me to updated documentation on how to do this? We're running a FAS 3240 HA.