With the Steamcontroller can be hit & miss at times (i own 2). Best to check & see if asseto corsa will support it. You may need to go with an xbox compatiable controller.
Now if you remember a user whom has run Assetto corsa here
Put @username & this will notify a user your looking for their input.
I think if mem serves @cmm or @jonnypanic may have experience with revive with assetto.