Kundensport has the right idea....
One suggestion:
Instead of using rivets to fasten the strap, use a second strip of aluminum to "pinch/clamp" the strap with(putting a fastener on either side of the leather, not through it). This way, when the leather/holes stretch, you can loosen the clamp, readjust the strap and tighten.
Works great.
Todd Rudaitis
Rennprojekt