Thanks to the "Mod Month" thread, I think I found what I am looking for...
For the older Performers- just for modification purposes:
In the US, Mr Heater sells an adapter fitting called a "Steak Saver" $$$, and its essentially a bulk tank refill fitting for a few bucks at cHina Freight!
I'm guessing the fitting, just past the regulator, is what opens and closes flow of the propane? Fiddling around with the one I have, seems the one in the pic, posted by swamprb, is in the closed position.