There are two ways to place tracking scripts on your site: 1. You can customize Success and Failure result pages of WorldPay and add tracking code to them using the following knowledge base article: http://support.worldpay.com/kb/customising3/result_pages/ppcg_3000.html 2. It is possible to set up Callback function in your WorldPay account using the manual http://support.worldpay.com/kb/reference/faqs/callback_faqs.html#callback_configure Then, you can add tracking code to field 'On Success Message' on 'Final Checkout Settings' page of WorldPay system in Viart Shop.