Machka,
I'm sorry about the problem. You should not listen to bad advice. If I remember correctly, I was with you and Rowan when you bought it.
My Ortlieb bar bag has snaps. I 'd think that a sail maker/repair or awning maker could install snaps and they would still be waterproof. Also contact Wayne at the Touring store for information about a fix:
TheTouringStore.com, Ortlieb Panniers & Packs, Tubus Racks, Lone Peak Packs