Installing a Tip-out Pop-Out Tent in cargo trailer?

Iv always liked these Tip-out Pop-Out Tents and wondered how difficult it would be to install one in a older enclosed featherlite 4926 cargo trailer? I know once you cut the opening you would have to weld in horizontal aluminum headers.. So, would you have to remove the exterior aluminum skin (very difficult) , or be able to pry the skin away enough to cut the studs shorter and weld in the header? I cant imagine being able to weld the backside of the header with the skin in the way.

Thanks!

http://www.united-trailers.com/Pop-Out-Tent

http://www.fthr.com/products/car-trailers/bumper-pull/4926-car-trailer