You have no buttons on the CP?

Not even player one start? P1 coin?
'Cause if you have at least two, just remap in mame's gerenal inputs "UI left" and "UI right" to any two buttons. You see, "wiggle joystick left and right" works because UI left and UI right are mapped to the joystick by defaut.
If you only have one button, try mapping it to both UI left and UI right. Might work.