Hi Rhino,
I use SPAD.neXt & have assigned the G1000n3 commands for pln, proc etc to buttons if that's any help. I have also assigned the C1000n3 Fms up & down events to the outer & inner rotating knobs of one of my Saitek Radio knobs when in XPNDR mode which works nicely. I then assigned both Select with a short press & Enter with a long press to the ACT/STBY button beside the knob. Other important FMS buttons are assigned to the Saitek Auto Pilot when in CRS mode as I have a QGMC710 auto pilot module which works brilliantly & has made the Saitek redundant.
Cheers