anchor.diff:  code_change(_OldVsn, State, _Extra) ->
       {ok, State}.
   
  +
   %%--------------------------------------------------------------------
   %%% Internal functions
   %%--------------------------------------------------------------------
   
  -%%--------------------------------------------------------------------
  -%% Function: start_generate_request(Method, URI, ExtraHeaders, Body)
  +
  +%%--------------------------------------------------------------------
  +%% Function: start_generate_request(Method, Referer, Referee, ExtraHeaders, Body)
   %%           Method       = string(), SIP method
  -%%           URI          = sipurl record()
  +%%           Referer      = contact record()
  +%%           Referee      = contact record()
   %%           ExtraHeaders = list() of {Key, ValueList} tuple()
   %%           Body         = binary(), request body
   %% Descrip.: Part of the startup functions. Build our initial request
  
positive.code: 	undefined ->
  	    {stop, "INVITE terminated prematurely", State};
  	ReferPid when is_pid(ReferPid) ->
  	    io:format("INVITE transaction (~p ~p) terminated~n", [Pid, Branch]),
  	    {noreply, State#state{invite_pid = none}}
      end;
  
  handle_info({clienttransaction_terminating, Pid, Branch},
  	    #state{refer_pid = Pid, refer_branch = Branch} = State) ->
      io:format("REFER transaction (~p ~p) terminated~n", [Pid, Branch]),
      NewState = State#state{refer_pid = none},
      case State#state.invite_pid of
  	undefined ->
  
negative.code: %% Returns : NewState = state record()
  %%--------------------------------------------------------------------
  received_invite_2xx(Response, State) when is_record(Response, response), is_record(State, state) ->
      Dialog =
  	case State#state.dialog of
  	    undefined ->
  