Snap roll on trainer switch?

One thing I enjoyed on my 12S original firmware was the option to program a snap roll on to the trainer momentary switch. Basically you pull the switch and it maxes out your rudder elevator and ailerons until you let the switch go. There was a spot in the GUI where you could program two or three different snap rolls and switch between them in the menu. I have searched high and low and tried to duplicate this on my own in deviation and I'm having difficulties. Can anybody shed some light on this for me?
Running 4.0 on a 12s flying various full house aircraft.

I don't have any experience with the stock firmware, but you should be able to do what you want with a complex mixer on the rudder, elevator, and aileron channels. Add a mixer, change to the new page, set the switch to the trainer switch, curve to fixed, and scale to 100 or -100 depending on the direction. You'll have to do this for all three channels.

Got it. Perfect. I knew the big D would make short work of the task, had the solution not eluded me. For some reason I was trying to set up a virtual channel that had elevator rudder an aileron all in the same mixer. Do you have any suggestions on how I could store two or three different settings? Would you just do the same thing in each channels mixer separately? Like for example have the mix switch select between left snap a right snap or something else. But still having the trainer switch be the initiator of the function.
Thank you so much. Already tested and flown. I like this a lot as I do not have to switch into high rates to get full deflection of control surfaces. I'm going to mess around with it a little more and see if I can adjust the order in which the controls are moved, set up a delay or something. To fine tune the sequence for individual planes characteristics to fine tune the sequence for an individual Plains characteristics