Human tasks are added through the default.session.template property file that is baked into console server. You can override this using your own session.template file, which you need to put in an appropriate location (JBoss conf directory I think?).
Human tasks need the knowledge session injected, so they added this functionality. You can add your own human task implementations this way too.
The latest implementation to look at is
AsyncHornetQHTWorkItemHandler or AsyncMinaHTWorkItemHandler. They keep deprecating classes so it is hard to keep up. These use the AsyncGenericHTWorkItemHandler and AbstractHTWorkItemHandler in its type hierarchy. Once you get what they are doing, you can write a similar one that suits your needs.