I had the same issue a week or two ago and what an adventure it was. My local AD is terrible (Mayors Tampa)I made a phone call and visit in person with no help from them at all(and I have purchased watches there before). I ended up going to a local watch repair shop that came highly recommended from Old Northeast Jewelers and had one custom made which cost me $40. I have now vowed to NEVER loose that screw again! Good luck in your search and if nothing else I can have another one made for you(just email me).