Hey,

I'm creating a payment provider for Worldpay (using the form redirect method where a form is built up and redirected to Worldpay to handle the transaction) but I have a few queries regarding the Payment provider setup.

All methods in PaymentGatewayMethodBase return IPaymentResult however I do not wish to create a payment at this stage. I only want to execute payment logic when the user has returned from the payment gateway.

I'm currently overriding PerformAuthorizePayment to do the following:

protected override IPaymentResult PerformAuthorizePayment(IInvoice invoice, ProcessorArgumentCollection args)
    {
        HttpContext.Current.Response.Redirect( "/umbraco/merchelloworldpay/worldpaysurface/process?key=" + invoice.Key.ToString( ) );
        return null;
    }

which will throw an null ref when Merchello.Core.Gateways.GatewayEvents.CreateOrder is called.

Is there another way to execute the redirect without having to create a payment?

If that isn't possible and I create a payment, can I then update applied payment status on response of WorldPay? (when I have found the invoice of course) Or must I add a new payment?

Thanks! John