public function getAddUrlParams()
    {
        if ($this->_aAddUrlParams === null) {
            $this->_aAddUrlParams = $this->getBaseAddUrlParams();

            // appending currency
            if (($iCur = \OxidEsales\Eshop\Core\Registry::getConfig()->getShopCurrency())) {
                $this->_aAddUrlParams['cur'] = $iCur;
            }
        }

        return $this->_aAddUrlParams;
    }