If you're going to have someone else do it, it should be easy to find someone. All sign companies are basically decal companies now. They wrap entire cars, trucks, buses with decals all the time. Call a few - they'll know. I'm surprised the bodyshop didn't know - they would have stripe companies coming to repalce decals and stripes all the time. Any business trucks, etc., have decals that get replaced after paint.
If you're going to do it yourself, you can sue dishsoap, or buy the CORRECT application solution. They sell it at sign shops and from PheonixGraphics.com. It's a very slippery solution that dries slowly. And do it inside your shop at room temperature and have the right squeegie too - not something you 'think' weill work!
