it's a Network Attached Storage device
I think that is the main problem - it is a
storage device and that was what all the D-Link NAS boxes were originally designed to be. That is all we have ever used them for, to store data and backups. Unfortunately not all devices that can be connected to a network use the standard network communication protocols in standard ways and therein lies the problem.
At the moment I think that you are someone that should be looking at an HP ProLiant N40L micro server, installing Linux or win server on it. With 4 drive slots and the ability to have something like an Icy Dock hot swap caddy in place of the CD you end up with a full home server. (any questions about it pm me)
As a final thought I can see why people get frustrated when they push these simple NAS boxes to the limits and something falls over. I can also understand the frustration of people that find bits of equipment that one would think should communicate together but they don't because the communications protocols are not written to the standard but use some API that only works with one operating system. Unfortunately there is no answer to that last problem (we have been forced to run a copy of windows in a VM just to be able to help some clients sort out their problems).