Many thanks for the help.
If I can just two other questions:
The application I'm making makes the interaction with the user through the web designer. Therefore I'll need to run the process definition in a Servlet. As such I'm startin the process within the Servlet and the WorkItemHandler will be returning information to be sent to the user. As such isn't this the only way to do it? Because executeWorkItem is void I can't send it to the Servlet...right?