Where is onGameStart called from the DLL? Looks like its called from regenerateMap(). Is there some reason to not put the chokepoint call there? I would think that regenerateMap() wouldn't be called for scenarios, but if that were the case, then onGameStart wouldn't be called either.
I see Kael added a call to it in regenerateMap() for FFH, but in the original BTS code there is no call to onGameStart anywhere in the DLL. I think this means it must be called by the game engine code that was never released.