[villagetinker]

If your valence are like ours, they slip into aluminum tracks, real easy to remove or replace. However, finding something like what is pictured may be difficult. I would start with an internet search, possibly amazon and ebay to see what you can find. Double check measurements, and you should be good to go. The only other option I can think of would be a search of would be for suitable (marine grade??) canvas in the pattern you like, and then a shop to fabricate the valences.