Hi Ned,
I use Orange receivers with my Futaba FASST transmitters. On this set up, if you first switch off the failsafe on the Tx, you can invoke failsafe on the Orange RX, it works on all channels not just the Futaba "throttle" channel.
With my set, you simply turn on the rx then place the tx sticks , switches etc to where you want them to be in failsafe mode then press and hold the micro button on the rx for a second or two, when the LED flashes to confirm set. May not be the same on Spektrum version of the rx of course