public function loadOrderFiles($sOrderId)
    {
        $oOrderFile = $this->getBaseObject();
        $sFields = $oOrderFile->getSelectFields();
        $sShopId = \OxidEsales\Eshop\Core\Registry::getConfig()->getShopId();

        $oOrderFile->addFieldName('oxorderfiles__oxarticletitle');
        $oOrderFile->addFieldName('oxorderfiles__oxarticleartnum');

        $sSql = "SELECT " . $sFields . " ,
                      `oxorderarticles`.`oxtitle` AS `oxorderfiles__oxarticletitle`,
                      `oxorderarticles`.`oxartnum` AS `oxorderfiles__oxarticleartnum`,
                      `oxfiles`.`oxpurchasedonly` AS `oxorderfiles__oxpurchasedonly`
                    FROM `oxorderfiles`
                        LEFT JOIN `oxorderarticles` ON `oxorderarticles`.`oxid` = `oxorderfiles`.`oxorderarticleid`
                        LEFT JOIN `oxfiles` ON `oxfiles`.`oxid` = `oxorderfiles`.`oxfileid`
                    WHERE `oxorderfiles`.`oxorderid` = '" . $sOrderId . "' AND `oxorderfiles`.`oxshopid` = '" . $sShopId . "'
                        AND `oxorderarticles`.`oxstorno` = 0";

        $this->selectString($sSql);
    }