whew, it works at least! I success to save my first task with the correct potowner.
I think other change will be needed to Taskorm.xml, but for the moment I just add :
<entity class="org.jbpm.task.Task" metadata-complete="false">
<attributes>
<id name="id">
<column name="id" />
<generated-value strategy="IDENTITY "/>
</id>
</attributes>
</entity>
<entity class="org.jbpm.task.I18NText" metadata-complete="false">
<attributes>
<id name="id">
<column name="id" />
<generated-value strategy="IDENTITY "/>
</id>
</attributes>
</entity>
<entity class="org.jbpm.task.Content" metadata-complete="false">
<attributes>
<id name="id">
<column name="id" />
<generated-value strategy="IDENTITY "/>
</id>
</attributes>
</entity>
after named-queries and change the entity mapping tag for jpa2:
<entity-mappings xmlns="http://java.sun.com/xml/ns/persistence/orm"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence/orm orm_2_0.xsd"
version="2.0">
See you next configuration problem.
Regards,