public void beforePhase(PhaseEvent event)
	{
		FacesContext facesContext = event.getFacesContext();
		HttpServletResponse response = (HttpServletResponse) facesContext
				.getExternalContext().getResponse();
		response.addHeader("Pragma", "no-cache");
		response.addHeader("Cache-Control", "no-cache");
		// Stronger according to blog comment below that references HTTP spec
		response.addHeader("Cache-Control", "no-store");
		response.addHeader("Cache-Control", "must-revalidate");
		// some date in the past
		response.addHeader("Expires", "Mon, 8 Aug 2006 10:00:00 GMT");
	}