All informations given above are still valid and applicable.- Of course FSUICP should be upgraded to latest version.Additionally I recommend to assign a key command to "Brakes anti-skid ON/OFF" in the Controls menu.(although small GA planes are normally not equipped with this system)This system must be activated again each time when the sim has been started or when the aircraft was changed.Just give it a try.
In P3D open tabOption-Controls-Key AssignmentsSearch for: "Brakes anti-skid (on/off)" and design a key for this (press new).Most of the keys are already taken, so you might choose 2 keys- CTRL and (your choice)