We had to do this on the in-laws Montana this spring. It clearly stated not to run the motor in reverse. In and out was controlled by the solenoids. It also stated to use the 9 volt battery out of the smoke detector to energize the proper solenoid to make it go where you wanted it to. The instructions were all very clear in the owners manual.
Track down your manual and read it. It seams as though there are a few different ways to accomplish this task. Make sure you have the right one or you could damage the system