The user switches between order step 4 and 5 within the same browser window to WorldPay. If the transaction succeeds, the browser switches back to order step 5, otherwise the user can select a different payment method in step 3. The order will only be saved if the transaction on the WorldPay site has been processed successfully

 

 

The module does not change any of the shop data sets (apart from front-end templates) and so the maximum update and upgrade ability can be ensured.