Dave:

I cut an arc shape about two inches wide from a thin piece of aluminum, wrapped the fabric over, and poly tacked it on the back side. The arc shaped section of aluminum extends from the frame members on either end.

I did this after the fabric was shrunk and painted, when I discovered the issue. If I were doing it again, I would again put a large section of fabric in that area, shrink the fabric, then glue the aluminum in place. Then cut it out and fold it over the back side and glue on the back side as well. The reason for shrinking it first is the thin aluminum wont take much tension.

Unfortunately I don't have a picture.

Chuck