I haven't done it on a Jeep, but I have done it with 700r4's.
It just takes a toggle switch to flink the solenoid. Since that signal is from the PCM, I'd use a diode to isolate it from the PCM - or better yet, let the toggle switch (2 pole) disconnect it from the PCM at the same time it engages the converter.
Check the FSM to make sure to PCM isn't grounding the solenoid to activate it rather than +12 volts.
He He - when you forget to unlock it and and come to a full stop, the engine will die.