DAX 2012. Как споймать ошибку try catch внутри транзакции?

[wojzeh]

// to write your log from inside of another transaction
	static public void insertExtEventLogInSeparateConnection(RefRecId _lineRecId, str _guid, str _logSource, str _logStr)
    {
        ExtEventLog         log;
        UserConnection      connection;
        int                 ttsLevel    = appl.ttsLevel(); //here you can check if you are inside of a transaction
        str                 errMsg      = strFmt("Cannot add event log '%1:%2:%3'", _guid, _logSource, _logStr);
		// let's create a separate connection
        try
        {
            connection = new UserConnection();
            connection.ttsbegin();
            log.setConnection(connection);
            log.InstructionDocLineRecId = _lineRecId;
            log.TaskGUID                = _guid;
            log.LogStr                  = _logStr;
            log.LogSource               = _logSource;

            log.doInsert();
            connection.ttscommit();
        }
        catch
        {
            throw error(errMsg);
        }
        finally
        {
            if(connection)
            {
                connection.finalize();
            }
        }
    }