Carriage return in CRichEditCtrl

In MSVC 4.2, I have an multiline edit box of type CRichEditCtrl, and every line I insert goes to the first line. I tried to add EOL, \n, \r, \n\r, \r\n and nothing helps. Any hint?

        CRichEditCtrl   m_log;
        ...
        sprintf(log_msg, "Current script file: %s\r\n", scrname);
        m_log.SetWindowText(log_msg);

        sprintf(log_msg, "Current message file: %s\r\n", msgname);
        m_log.SetWindowText(log_msg);