public function addItem($p_strName, $p_iQuantity, $p_iGrossAmt, $p_strEAN = "") {

    if (empty($p_strName) || empty($p_iQuantity) || !isset($p_iGrossAmt)) {
      throw new GiroCheckout_SDK_Exception_helper('Name, quantity and amount are mandatory for cart items');
    }

    $aItem = array(
      "name" => $p_strName,
      "quantity" => $p_iQuantity,
      "grossAmount" => $p_iGrossAmt
    );

    if (!empty($p_strEAN)) {
      $aItem["ean"] = $p_strEAN;
    }

    $this->m_aItems[] = $aItem;
  }