code: public ServletTimer createTimer(SipApplicationSession appSession,
  			long delay, boolean isPersistent, Serializable info) {			
  		
  		MobicentsSipApplicationSession sipApplicationSessionImpl =(MobicentsSipApplicationSession)appSession;
  		
  		if (sipApplicationSessionImpl.isValid() == false) {
  			throw new IllegalStateException("Sip application session has been invalidated!!!");
  		}
  		
  		if (!sipApplicationSessionImpl.hasTimerListener()) {
  			throw new IllegalStateException("No Timer listeners have been configured for this application ");
  		}
  		TimerListener listener = sipApplicationSessionImpl.getSipContext().getListeners().getTimerListener();
  		ServletTimerImpl servletTimer = createTimerLocaly(listener, delay, isPersistent, info, sipApplicationSessionImpl);				
  		
  		return servletTimer;
  	}
docs: /*
  (non-Javadoc)
  @see javax.servlet.sip.TimerService#createTimer(javax.servlet.sip.SipApplicationSession, long, boolean, java.io.Serializable)