You have not provided any info to help you.
Errors, screenshots, etc.
That said, the HP D2D is either a VTL or a NAS device that you can create a B2D folder on.
With the 12.0 licenses, if you use it as a VTL, it'll cost you a fortune. Thus, you should just use the CIFS share, and backup to disk. However, with BE2010, there is a new VTL unlimited license model that makes the devices more affordable from a licensing standpoint...