War Project with dependency to jetty-websocket with scope provided throws ClassNotFoundException on jetty:run

I wrote a maven war project that contains a jetty websocket implementation. I've defined the dependency to jetty-websocket as 'provided', to keep it (and its transient dependencies) out of the resulting war file. But doing so makes it impossible to test this with the jetty:run goal, as the webapp throws an ClassNotFoundException for the jetty websocket classes. Setting the useProvidedScope in the plugin configuration to 'true' did't improve the situation, as the plugin filters system jars from the provided dependencies. before adding anything, and jetty-websocket is in the system jars.