I don't think that part is PVC, so I doubt if it will glue back on...
I think you might have to replace it. Shouldn't be too bad.
If the factory was open I'd say call them, but they aren't. But I think it is a pretty standard part.
If the size is right you should be able to change it with something like this.
http://www.rvwholesalers.com/catalog...e-10-1468.html
If your dealer is close I bet they would have one in stock...
HTH, Keith