Don't know that I would call 2ft "slightly" shorter, but whether or not it would work OK depends on your original setup. I presume you are talking about how far the awning would extend? If you can extend the torn awning, mark where 2 feet shorter would be, retract the awning to that point, and see how that would work/how you would like it. Awning arms vary in style and function, and some would work well at various extension lengths while others would not.
Paul (KE5LXU) ...was fulltimin', now parttimin'
'03 Winnebago UA 40e / '05 Honda Odyssey toad