I have not had good luck with Velcro in a UV environment. Bungee straps might be an option. Not sure of your application.
I have used dual lock and it's great. Don't know if there's a version of it that can be sown to fabric. As others have said, Velcro doesn't hold up very long when exposed to UV. Perhaps if it was covered with some kind of flap?
Ken
Agree w Commodave - moving zip may work.How do you get zippers back together when they are just a little bit short from elements? Glass will not meet and leaks are result. It is making me crazy!