protected function getAvailablePaymentListAsString()
    {
        static $sPaymentMethods = null;

        if (null === $sPaymentMethods) {
            $sPaymentMethods = '';
            $oPaymentList = $this->getAvailablePaymentList();
            if (null !== $oPaymentList) {
                if ($oPaymentList->Length() > 0) {
                    while ($oPaymentMethod = $oPaymentList->Next()) {
                        if ('' != $sPaymentMethods) {
                            $sPaymentMethods .= ', ';
                        }
                        $sPaymentMethods .= $oPaymentMethod->GetName();
                    }
                }
            }
        }

        if (!is_string($sPaymentMethods)) {
            $sPaymentMethods = '';
        }

        return $sPaymentMethods;
    }