Thanks for yopur answer.
Yesterday I tried to use JPA2 by replacing JBPMorm.xml mapping with JBPMorm.xml-JPA2 (http://mriet.wordpress.com/2012/04/03/jpa-2-with-drools-and-jbpm/), but I got many errors related to entity mapping version:
Caused by: org.xml.sax.SAXParseException: cvc-complex-type.3.1: Value '2.0' of attribute 'version' of element 'entity-mappings' is not valid with respect to the corresponding attribute use. Attribute 'version' has a fixed value of '1.0'. (see log attached)
so I rolled back to the prevoius configuration.
Can you explain me how to change jpa version (consider I'm new to Jbpm)?