NetTuts.com has continued their series showing how to integrate a custom payment method into your OpenCart instance with part three of the series. In this tutorial they focus more on the frontend aspects, creating controller and model handling for the new method.

If you've been following along with this series, you should be familiar with the kind of file structure we set up for our custom payment method in the back-end. [...] We'll use a similar kind of file setup for the front-end section as well.

He starts with the controller, building a handler for the Custom method, doing some data filtering and getting the order information. He walks you through what each of the lines are doing and shows how to output the result back to a view. He also includes the model code needed for the custom payment method as well as language/template files to display the form needed to gather the necessary data.