You don't need to do that either.
Turn the key OFF. Make a small jumper wire, bare strands on one end, a ring terminal on the other. Attach the ring to a solid ground somewhere. As you turn on the key, the lights on the M-Unit will begin to cycle. WHILE ITS CYCLING, touch the bare end of your jumper to the screw on the CONFIG port and hold it there. This trips the m-unit into SETUP mode. By tapping the same screw with your jumper, it will index through the menus, and you double tap the screw to move to the Option side of the menu.
Watch the lights on the left. It progresses from top to bottom to indicate which menu option you are on, then the light will switch to the right (with the double tap) to show you which configuration you are choosing. Double tap again to jump back to the left, and tap to move to next menu. When you're done, cycle the power. Finished.
Even with a small momentary switch, the selection behavior is the same, you just don't make a jumper wire.