You need to familiarize yourself with the compatibility lists, both for hardware and software. All your answers lie within.
http://www.symantec.com/business/support/documentation.jsp?language=english&view=comp&pid=15047
From what I recall, ONLY NetApp, EMC, and IBM NAS devices are supported in BackupExec in regards to NDMP. It's been like this for as long as I can remember.
You'll need to backup the CIFS shares themselves, which is REALLY REALLY slow. You should upgrade to NetBackup to support that new device, contact your local Symantec rep or reseller and tell them you want NetBackup, there are upgrade part numbers. ;)