public function getMailContent($type = Kwf_Model_Mail_Row::MAIL_CONTENT_AUTO)
    {
        if ($type == Kwf_Model_Mail_Row::MAIL_CONTENT_AUTO) {
            $ret = $this->_getHtmlMailContent();
            if (is_null($ret)) $ret = $this->_getTextMailContent();
            return $ret;
        } else if ($type == Kwf_Model_Mail_Row::MAIL_CONTENT_HTML) {
            return $this->_getHtmlMailContent();
        } else if ($type == Kwf_Model_Mail_Row::MAIL_CONTENT_TEXT) {
            return $this->_getTextMailContent();
        }

        return null;
    }