Vehicle with 6 wheels

hello evry one.
i am a french guy so sorry for my english.
ok, i try to make a vehicle with 6 wheels, i use a plugin EnhancedVehicle Movement.My 6 wheels whork great
but when i turn the steering wheel the back wheels turn in the same a front wheels.
I try to put a negative valu in steer angle of back wheels but i can’t.
i am new in unreal engine 4, so where i put a negative valu for my back wheels in oposite with my front wheels.
Thank you for your time…;base64