To activate the support legs you must leave the vehicle and the control levers of the swap bodies operate!
Keys N + M to retract the supports
Keys J + K to extension of the legs
If the supporting feet are fully retracted, green marks are visible on the control levers!
If the supporting feet are fully extended, to be the control levers visible red marks!
To hide the front hydraulics have to get out of the truck, stand in front of the truck and press the R button.