I had almost the exact same setup at one point, even down to removing the HD cage!
I do know that pump well, and I also agree that it needed badly to be suspended. One thing I always thought I'd try (but never got around to) is buying several of those silicone keyboard wrist rests and placing it on them. I think the rests are quite cheap. You may want to try that.
I also found that if you suspend it from the hoses, it worked pretty good too. Does that make sense? Maybe if you wrapped the wrist rest around the output hose and then attached the wrist rest to the case (so nothing was actually touching the body of the pump) that might work pretty good.
In my system, I had the pump external to the case (as was the giant reservoir) so I had the space to prop it up on several pillows!
Hope my suggestions help, and good luck!