This are the steps I used and it worked without a hitch lol

Add +AHMU to the FA for both CAS and FRM

AHM Module
LAENDERVARIANTE_AHM to "us"

PDC MODULE
ANHAENGERKUPPLUNG aktiv -> nicht

CAPPL module
ANHAENGERKUPPLUNG aktiv -> nicht


Here's a pic of mine with the OEM aero kit.