Hi Alistair,
You can use jBPM5 directly inside your web application. Do you know how to use JSP and JSF? For example if you are using JSP you will probably want to create a Servlet which will contain the logic for your presentation (MVC fashion). That servlet can use the same APIs that you are using on the test to interact with the processes and then propagate the results to your JSP as in any JSP application.
Cheers