rFactor g25 pedals not responding correctly?

I am using rf and i cant seem to get the accelerator correct, its only accelerating when i get to the last 30 percent of pressing it, same for brake, should i adjust this in the game or should i do it in the g25 profiler? also am not quiet sure what the advanced tab is doing in the controllers setting in rfactor, is there any documentation on what the throttle mapping does etc? Any help i would greatly appreiate