APC Battery Backup

I am a new owner of a My Book Live Duo (2 x 3TB RAID 1) and have been trying to get my APC ES-650 to connect to the Duo but keep getting an “unrecognized device” is plugged into the USB.  I have messed around a little on the Duo using the UNIX emulator but I know enough to be very dangerous and do not want to brick the DUO.  Anybody have any luck using a battery backup?

I think the USB port on the Live DUO is only for external storage devices such as hard drives, USB, etc.  I would  just plug the DUO in the UPS and not worry about the USB cable. 

I would like the MBLD to shut down gracefully after a power outage.  I have it plugged into the APC right now but just trying to get it to work.  I have been looking on the APC website too, just wondering if anybody had done this before.