Tron Controls on Game Elf 900 in 1

[FlynnsBarcade]

I built up a game system using a Game Elf 900-1.  Lots of buttons, a spinner and trackball.  The spinner and track ball work well with games such as Arkanoid, Centipede, etc.  I'm having an issue with Tron.  Since you cannot reassign the inputs in the Game Elf (slight disadvantage over this cheap alternative), I wanted to put in a "switch" for changing the controls to work better with the Tron game.  Here is my issue:

For the Game Elf, Tron controls are as follows:
Player 1 Joystick : up/down/left/right work as expected
Player 1 Button A&B are CW/CCW rotation
Player 1 Button C is Fire.

I can put in a switch (actually plan on using a bank of relays to switch game control modes) to tie the fire button to my joystick's fire button.
My issue comes in with the Spinner.  The spinner on the Game Elf is tied to the X+ X- inputs, so it doesn't do anything for Tron.  I tried to connect the spinner outputs to Button A&B, but that results in the game'' gun rotation to jog back and forth (as expected since this is how the spinner works).

Q1: Is there another type of spinner I can use to connect to the A/B button inputs?
Q2: Is there some type of electronic interface I can use to make my current spinner work with the A/B buttons?
Q3: Any other solutions?

Thanks
-Eric