Do you have access to files, a drill, and taps? If so, this is a possibility which I have seen done this year. Here is a very rough sketch not to scale:
If you have a file, you could file a flat on one side of the pulley, drill and tap holes, make a little washer plate (regular washers would also work), then fasten with two button heads. It might be a good idea to melt the edges the the hole with a lighter, or even make the holes with a soldering iron to prevent any fraying. Also, you might want to find a way to increase the size of the flanges to prevent the webbing from tracking off.