I tried a search but did not find anything. Here is a little video on how I replace a sewed in leg strap. You will need;
1. sewing awl with thread
2. Scissors
3. needle nose pliers
4. a new strap
5. Box cutter or exacto knife.
I just uploaded the video so it might take a little bit to show up on Google video.
Basically you cut the old strap out and sew the new one in. The whole procedure might take 5 to 10 minutes depending on how much work you want to put into it. This will save you money and also will open your mind up to experimenting with different strap set up. Please let me know if you have questions.
How to change a leg strap - Google Video