protected function _appendCustomLangFiles($aLangFiles, $sLang, $blForAdmin = false)
    {
        $oConfig = \OxidEsales\Eshop\Core\Registry::getConfig();
        $sAppDir = $oConfig->getAppDir();
        $sTheme = $oConfig->getConfigParam("sTheme");
        $sCustomTheme = $oConfig->getConfigParam("sCustomTheme");

        if ($blForAdmin) {
            $aLangFiles[] = $sAppDir . 'views/admin/' . $sLang . '/cust_lang.php';
        } else {
            if ($sTheme) {
                $aLangFiles[] = $sAppDir . 'views/' . $sTheme . '/' . $sLang . '/cust_lang.php';
            }
            if ($sCustomTheme) {
                $aLangFiles[] = $sAppDir . 'views/' . $sCustomTheme . '/' . $sLang . '/cust_lang.php';
            }
        }

        return $aLangFiles;
    }