Hello,
I have made it to work! The problem was in Hibernate 3.6.0 bug.
http://http://opensource.atlassian.com/projects/hibernate/browse/HHH-4617
The soulution was to upgrade Hibernate 3.6.0 (on JBoss 6.0 Final) to Hibernate 3.6.3 Final.
a) I have copied hibernate-core-3.6.3.Final.jar and hibernate-entitymanager-3.6.3.Final.jar to JBOSS_HOME\server\default\lib
b) persistence.xml
<property name="hibernate.jdbc.use_streams_for_binary" value="false" />
Best Regards,
Krešimir