Description of problem: I haven't seen anywhere in the code a call to org.drools.runtime.StatefulKnowledgeSession.dispose() method which should be used to releases all the current session resources. Please see http://docs.jboss.org/jbpm/v5.3/javadocs/org/drools/runtime/StatefulKnowledgeSession.html#dispose()
As far as I know, we cannot do this. If you start a process, then dispose the session, when you try to move the process along in the business-central console, it will complain that the process's session was disposed.