My friend is building an S20 and as of the middle of February, 2016, the tech support guy at RANS said they are starting to produce mounting kits for the AP servos. Now, whether they are for the Garmin or the Dynon, I do not know, but you could call RANS and find out. I suspect it's a Dynon mount, as my friend has indicated a preference for Dynon avionics. If you get a firm response from RANS, maybe you'd post it here.
I'm trying to figure out mounting brackets for my new S7. The mounts for the old S7 don't work for me.