Help? SD vest question?

My cousin's SD vest straps got destroyed when we washed it tonight. And we can't fix the straps to were they would hold. We are going out of town on tuesday and the new vest we ordered wont be here until after president's day. So to my question, is it ok to buy a light weight jacket from the pet store and sew on the patches to the jacket? The trainer suggested to get a backpack but I couldn't find one in a small size. We have all the paperwork and id cards from the trainer but it is easier to take him places when he has a vest on since he is a small dog. Any help would be greatly appreciated. Thanks.