I download the quicksave tool from the resources page and I can't get it to work. It says that it is enabled and that the hotkey is F5 but in-game it does nothing. Anyone got an idea how to get it to work?

I want to bind left mouse to lean backwards on vehicle but when I do that the game removes the fire bind of left mouse button from both on foot and in car. Is there anyway I can get around this? I've heard using other applications like skeys will get you to do this but I tried it and can't get it to work. Please can someone help me with this?