I did it!
You just have to send a M911 with an absurd voltage way over your current vin, and the auto-pause will trigger right away.
So instead of having the M911 in confg.g, you put the full command in your trigger file and you are all set.
Just remember y your duet doesn't power cycle, you will need to send an m911 with more beliable values, but if your duet really did lose power, when you power up the duet again it will have the power-pause disabled.