code: public javax.servlet.RequestDispatcher getRequestDispatcher(String handler) {
  		MobicentsSipServlet sipServletImpl = (MobicentsSipServlet)
  			getSipSession().getSipApplicationSession().getSipContext().findSipServletByName(handler);
  		if(sipServletImpl == null) {
  			throw new IllegalArgumentException(handler + " is not a valid servlet name");
  		}
  		return new SipRequestDispatcher(sipServletImpl);
  	}
docs: {@inheritDoc}