Hi Caine,
I am not familiar with JPA. So I don't know how to use LocalContainerEntityManagerFactoryBean to replace LocalSessionFactoryBean. Could LocalContainerEntityManagerFactoryBean use hibernate's *.hbm.xml to mapping entity class?
The key point is the jbpm4 using org.hibernate.Session to access Database, So I am afraid at this moment, we couldn't use JPA directly. Maybe someone could provide a JPA DbSession implementation to achieve this feature.
For the TransactionManager issue, I think we could use the PlatformTransactionManager which was provided by spring, You could refer Developer Guide to get more information about how to integrate spring and jbpm-4.x
http://docs.jboss.com/jbpm/v4/devguide/html_single/#springIntegration