I'm starting to install my Jegs cage in my truck. I want to put tube out the back of the cab into the bed. I have been reading about mounting the cage to the body only and not tying into the frame. How do you tie into just the body in the bed since the bed is hard mounted the the frame and the bed and body are 2 entities? I thought maybe putting a body mount under the tube in the bed area???? Any ideas? Thanks.