Not sure if you're still there or not, but you can basically use the same method they call out in the Jetcat instructions - set your max and min throttle for +/-75% ATV. I use my trainer switch for throttle kill, so this becomes a single channel operation per the Jetcat manual. Assuming you're using a PCM receiver, and your transmitter is set to operating in PCM, go to your F/S menu, and enter a value in channel 3 (throttle) so that you go at or below your turbine kill switch setting.

You may want to go set other control surface settings, too for failsafe, in order to slow the model down (gear down, or speedbrakes out, etc).

When failsafe is properly set, you should be able to turn your Tx off, and the little F~ Failsafe symbol will come up on your GSU.