Just in the same way, you only need to create a single persisntece unit and use that for both.. session and local human task service.
Here is an example: https://github.com/Salaboy/jBPM5-Developer-Guide/blob/master/chapter_08/jBPM5-PersistentProcess/src/test/java/com/salaboy/jbpm5/PersistentProcessTest.java#L375
Try it and let us know if you have some troubles.
Cheers