/// <summary>
        /// Send an instance message
        /// </summary>
        /// <param name="dest"></param>
        /// <param name="message"></param>
        /// <returns></returns>
        public int sendMessage(string destAddress, string message, int accId)
        {
            if (!pjsipStackProxy.Instance.IsInitialized)
            {
                return(-1);
            }

            string sipuri = "";

            // check if name contains URI
            if (destAddress.IndexOf("sip:") == 0)
            {
                // do nothing...
                sipuri = destAddress;
            }
            else
            {
                sipuri = "sip:" + destAddress + "@" + Config.Accounts[accId].HostName;
            }
            // set transport
            sipuri = pjsipStackProxy.Instance.SetTransport(accId, sipuri);

            return(PjsipMethods.dll_sendMessage(Config.Accounts[accId].Index, sipuri, message));
        }