washer? is that what you meant by a little metal ring on the valve? I wouldnt put anything on a valve behind/under the rim ..
A stem washer protects the chrome rim from being scratched by the nut.. but these tubes can go on a wide variety of bikes and rim styles.. If the washer interferes, don't use it.
I don't understand about the "bead" not sitting right.. A tire's bead goes all the way around the tire.. A bead is a steel wire core in the tire's inside edges..