how do you have it wired up? did you get the wire harness when you bought the spinner? I have one of these, but mine is interfaced with an optiwiz. what axis do you have it attached to? With mine, I have the harness, and I attach it to the Z axis of the interface (this could easily go to the X or Y if I wanted to). The white wire(S1) goes to the ZA axis, green (S2) goes to the ZB axis, RED to +5v, BLACK to Ground.
In windows, my trackball acts as a mouse (X & Y axes), and my spinner acts as a scroll wheel (Z axis).