Sorry, for some reason i missed that part where you told it's a USB device.
I guess that BE cannot and wont handle it like normal tape device, and you should use it wit BE like Removable device.
Can you try to add your RD1000 to BE from Devices, Removable Backup to Disk folder? From there you would create new removable backup to disk folder and show your RD1000, i assume that it shows up as removable storage when looking from Windows Explorer?
Before that, you should disable Windows's "Removable Storage" service.
Edit: Check this link;
http://www.experts-exchange.com/Storage/Backup_Restore/Backup_Exec/Q_23156014.html