you'll have trouble finding Look pedals with straps on them. You'll either have to make them yourself, or find a pair that someone has made and is willing to part with. The screwing the strap to the underbody of the pedal is the simplest and easiest option. All you need is a fairly small woodscrew for each pedal, maybe two. Just glue the strap to the pedal where you want it to sit, then screw the strap down with the woodscrews on the bottom of the pedal near the sides. Make sure to use a washer underneath the woodscrews, and make sure that the woodscrews are of the mushroom head variety, not the conical countersunk kind. You'll probably have to pierce the strap before you try to screw it down.