Change deferredResult http status code on timeout

I´m using deferredResult on Spring MVC, but using this code, the timeout still are sending back the http code 503 to the client.

      future.onCompletion(new Runnable() {
        @Override
        public void run() {

            if(future.isSetOrExpired()){
                response.setStatus(HttpServletResponse.SC_NO_CONTENT);
            }
        }
    });

Any idea what else to try?.

Regards.