Replacing Glass In Storm Window and I need to find a place to buy new gasket

My glass in my storm door became loose so I took it out. The gasket holding it in place broke in several places. No one has the gasket and they tell me to buy a new door. No one will help me or tell me how to fix it. I have spent hours looking for a gasket and finally found this site. Someone told me silicone would work. Someone else told me it wouldn't work. No one carries the gasket. I thought maybe it was a marine glazing gasket, but I can't find that either. I thought a magnet gasket might work, but it is not for glass. It is a double hung aluminum storm door and this glass is stationary on the bottom. It fits into the opening. The glass is perfect. Right now I have foam board on the door and I want to put the glass in myself. Surely, someone has a solution to this simple problem.