oh, thing here is about changing a things instead of a driver. like driver (rfactor speaking) would lead it's HUD to pit menu and then he would change values of his pit settings - tires, fuel, etc....so thing is to make a remote button control. as by the default that buttons are UP, DOWN, LEFT, RIGHT (Arrows, +enter needed) it's aonly a remote keyboard thing so to press some arrow in software (client) and for it to acts on server pc like he pressed that arrow (that's the easiest way of getting it to work.
another part of it is feedback as you have to see current values (like on video when you click on pitwall-project -> engineer you see like they have feedback of on what pit option you are and it's value (ie Tires: Soft ; Fuel: 70L ; ...etc).
so, what we need would be something like remote keyboard (something what a backdoor software can do, but then it would make problems with anti virus), but added to software so it would have only 5 commands - arrows and enter...(or buttons directly from rfactor, eventho i'm not sure how to edit that without using ram) + a viewable feedback also on client version of current menu