Try an APC Back-UPS 725VA or 750VA
I've tested with both those UPSs and they have the ability to work. Or it could be on yours, that it is trying to use the wrong driver. I had enough problems with UPS functioning on my DNS-323 that I just use Fun_Plug and first install your own version of NUT (Network UPS Tools), and in the start script, make it kill the factory processes relating to the built-in DNS's UPS tools (ie upsd, and upsdrvctl), and then I copy all of the files that NUT needs to run into the / ramdrive space, and then start the processes all from the startup script. NUT comes with upsmon as an extra component that DNS firmware does not include and so far, this is the only daemon that I have used that has been able to successfully shutdown my DNS-323 when it should go down. In the upsmon.conf file you can set parameters like what state the unit should shutdown (ie On Batt, or Low Batt, etc). I got mine working like a charm now. You might need to search around to figure out what driver your UPS needs to start. I think NUT comes with 4 drivers and when you figure yours out, you need to specify which one to load in the ups.conf file. The one my APC uses is the usbhid-ups driver. The NUT package has samples in each of the conf files so if you install the package and then first start by reading each of the conf files you will learn a lot.
Another excellent page to read is here: http://wiki.dns323.info/howto:nut_ups
I think you could get yours working if you read all that stuff. I think this is the only way you'll get it working is if you do it yourself. Good luck waiting for D-Link to fix UPS support for a while. They may eventually get around to it, but I wouldn't hold your breath. It might be awhile.