Eh, "calibration" is a mess. Support mouse; jk, don't support mouse buttons. So then I configurated left and right mouse buttons as shift up/down with the virtual joystick method and it worked. Except I don't see a way to turn off LMB steer-lock while on track :| Mouse scrollwheel button instead of LMB to shift up works, but is very awkward to use.. Am I also seeing right that there is no way to adjust the linearity of mouse steering (only linear sensitivity)?
But hey, it's working.