Shortening an awning

I have a question on cutting a 20 foot awning and making the tube 15 feet. I need new awning material and my awning tube has a small dent at one end. I can easily get by with a smaller awning and I have the place to mount the 15 footer. My question is will the retracting mechanisms that are in the 20 foot tube work in the cut down 15 foot tube?

Thanks,