B200 build - help with x-plane command/dataref

Hi everyone! I'm starting a build of a B200 based on Carenado's version for X-Plane. I am starting with the autopilot they have for it. There is a button labeled "Push CRS Direct" and I am trying to get a physical button to work. I can get the rotary encoder working, but not the push botton, as I can't figure out what the command or dataref I need to trigger when the button is pressed. Any help??
http://www.mycockpit.org/forums/atta...id=12265&stc=1
Thanks!
EsqFlyer