Because the gateway isn't seamless you need to configure the payment gateway pages on their server. You also need to make sure you have set a valid Callback URL.
Worldpay will give you a username and password to your Management area with them. They call this the "Wordpay Administration Server". They also give you lots of ID numbers and this can be a bit confusing at first.
The cart is integrated using Select Junior. You must have and setup the cart to use an Installation ID that is linked to this program. Other programs will not work properly. The most important part of the configuration is to enter a Callback URL to use with the installation ID. Click on Configuration Options.
You should enter a Callback URL of:
where ww#.aitsafe.com is the name of the server your cart is setup on.
You must also tick the check-box: "Callback enabled?" If you do not setup a callback URL your orders will not be saved.
The callback itself returns a webpage similar to the standard Thank you page that we use here at Mal's e-commerce. It is up to you whether or not you actually display that page with the "Use callback response? option. You could alternatively setup and configure your Thank you page using Worldpay's customisation features.
No info servlet password or callback password is required. Leave them blank. They are for other integration methods not supported.
The account IDs represent the actual payment options you want to offer the customer. You can leave this blank in Admin here if you like and let Worldpay choose. However, we found that when it is blank ALL options were displayed which in my test accounts were:
Since we're not much interested in Worldaccount we entered the account ID only for the the second option and were able to get rid of references to Worldaccount from their pages.
URL to this page: https://www.mals-e.com/tpv.php?tp=16