protected function _toList($sListType, $sProductId, $dAmount, $aSel)
    {
        // only if user is logged in
        if ($oUser = $this->getUser()) {
            $sProductId = ($sProductId) ? $sProductId : \OxidEsales\Eshop\Core\Registry::getConfig()->getRequestParameter('itmid');
            $sProductId = ($sProductId) ? $sProductId : \OxidEsales\Eshop\Core\Registry::getConfig()->getRequestParameter('aid');
            $dAmount = isset($dAmount) ? $dAmount : \OxidEsales\Eshop\Core\Registry::getConfig()->getRequestParameter('am');
            $aSel = $aSel ? $aSel : \OxidEsales\Eshop\Core\Registry::getConfig()->getRequestParameter('sel');

            // processing amounts
            $dAmount = str_replace(',', '.', $dAmount);
            if (!\OxidEsales\Eshop\Core\Registry::getConfig()->getConfigParam('blAllowUnevenAmounts')) {
                $dAmount = round(( string ) $dAmount);
            }

            $oBasket = $oUser->getBasket($sListType);
            $oBasket->addItemToBasket($sProductId, abs($dAmount), $aSel, ($dAmount == 0));

            // recalculate basket count
            $oBasket->getItemCount(true);
        }
    }