code: public void addAuthHeader(SipServletResponse challengeResponse,
  			String username, String password) {
  		addAuthHeader(challengeResponse, username, password, false);
  	}
docs: /*
  (non-Javadoc)
  @see javax.servlet.sip.SipServletRequest#addAuthHeader(javax.servlet.sip.SipServletResponse, java.lang.String, java.lang.String)