Maybe im stupid, maybe im bling, but how can i bind buttons on a controller to steering (no axis)

Uhm... don't think you can.

Unless there's a setting for "steer left/right" in the controls page.

Get JoyToKey (google) and assign your Pad buttons to real Keyboard presses.

You must assign your pad's accelerate/brake etc buttons to various other keyboard keys as well because when you set up LFS to use KB mode, the other buttons on you Pad will not work on LFS.