Tab targeting will not work on gaming peripheral! Why?

This issue has been around for a very long time, and I've seen others bring it up in other forums. I have a gaming peripheral (Razor Nostromo) in which I have the scrollwheel up as my [TAB] key. I have it like this for every game and it works for every game I've played. Well over a dozen MMO's in the five years I've had it.

I can keybind with it just fine in the keybind menu. However, out of the menu and in the gameworld, the game does not register it as [TAB]. It does not register it as anything. So then I go back into the keybind menu, experiment with other keys, and it does not matter. Your game does not register any key I put into my scrollwheel. This is beyond frustrating. If you will not recognize tab being bound to my scrollwheel, could you at least provide a rationale for why you will not recognize it in the gameworld?

Would hazard a guess it is an issue with how the driver is interfacing with the DX9 input or something. Have you tried binding the wheel as a keyboard button (like, maybe TAB) in the Synapse software?