将自定义参数添加到PayPal

Question

我需要向PayPal发送自定义参数，然后使用IPNPaypal接收。

我添加了输入

    <input type="hidden" name="custom" id="custom" value="MyData">

    <div id="paypal-button">
    <input type="hidden" name="custom" id="custom" value="MyData">
    </div>

或者我需要在paypal.Button.render中添加此参数？

 paypal.Button.render({
                                        env: 'sandbox', // or 'production'
                                        commit: true, // This will add the transaction amount to the PayPal button
                                        payment: function () {
                                            return paypalCheckoutInstance.createPayment({
                                                flow: 'checkout',   // Required
                                                amount: newPrice,   // Required
                                                currency: currency, // Required
                                              // custom: 'Thisfromrender',   not working as well                                             
                                                locale: 'en_US',    // PayPal popup language
                                                landingPageType: 'billing', //billing is for guest, login is for PayPal
                                                enableShippingAddress: true,
                                                shippingAddressEditable: false
                                            });
                                        },

                                        onAuthorize: function (data, actions) {....

我缺少什么？