I used a program called spad.next it allows you see variables being passed through the simulator , some developers have variables visible and some do not.  so you can add all the local variables while the sim is live , flick your switches and dials.  Then you go back to Spad.next and look through variables that have changes most recently.  Those variables are mostly likely involved in the execution of your button / switch / dial.  Then through looking at Captain Sims other SDK documentation on other aircraft and how there variables are laid out and what they mean , it was a series of trial and error in determine how the L1011 is laid out.  That's a really quick look at how I figured it out.  I'm still finishing up the rest of the Autopilot and testing this evening, looking forward to flying some routes very soon!