Get an old patch cable and cut it near one of the jacks. Strip the cable to expose the ground wire and the hot wire inside making sure to leave enough insulator on the hot wire to ensure that the two wires are isolated. Twist each of the braided wires to make threm more manageable.
Now, plug the remaining jack into the control in jack of your unit. Touch the two wires together and see if your unit responds. If it does then you can hook them up to any non latching switch found in hardware stores (i.e. doorbell, buzzer etc.) and you got yourself a footswitch.
