Okay, so I ended up disassembling the control box on the cord to see what I could find out, and the answer here isn't, as I had originally expected, software related. Instead, this is coming down to shoddy craftsmanship.
All the leads connecting the board to the headset are strong, solid, through-hole soldered leads. Meanwhile the leads connecting the board to the USB cord are all surface mount... SMT works well for things that aren't being tugged on (solid state caps, transistors, resisters, etc) but anything that might get pulled away from the board should be through-hole mounted, as otherwise things will fall off.
But well-made solder joins rarely break, and these didn't either.. Instead, the lead, the solder join, and the copper track for the V- line all pulled off the board together in one fell swoop: effectively destroying any chance of the board ever working again.
Now to look at this headset, one might notice the rubber pull-stops on each side of of the control box and think "Oh, well you'd have to be really rough with the cables to snag them loose from the board" but the pull-stop ONLY secures the outer sheathing, which is elastic in nature whereas the wires inside are not. So with one slight tug on the cable between the PC and the control box, you've destroyed your headset.
This would have been such an easy problem to avoid, had Rosewill demonstrated any foresight whatsoever. They could have made the board just 3mm longer and done a through-hole mount of the USB leads without having to worry about the LEDs on the other side of the board. They could have simply added hot glue to the insides of the pull-stops so that the individual wires side didn't pull through the sheathing. They could have sealed the back half of the board (where all the mounting points were) in resin after they tested as working so nothing could break free from the board. They could have done this a million other ways, but they wanted to save every penny they could - and it ended up costing me.
So, now I'm sharing this story with anyone who cares to read it. If you look at my rig, you can tell I don't mind spending money on higher end tech - so long as it is well made. Rosewill failed this test. Their customer support failed to provide a solution. And the will simply never made another dime from me or Jen.