As I faintly recall I originally had to install my unsupported wheel kit using the standard keyboard profile.
And then afterwards applying the different axis and buttons from your wheel/pedals to this profile.
Afterwards you can change name of the custom keyboard profile to the name of your wheel.
You could also try to use another DD profile and then insert your wheels ID into this.
Open the steering_wheels.xml and Keyboard.rcs to check the changes you can make/are making.