(JPA and JSF 2.0) Lazy Loading problem with Set<> in Hibernate, OpenJPA etc (works with Eclipselink!)

With the Demo Project down below,
(default Parent/Child or Box/Items project)
you will face following two errors:

• You did set up some Items. As soon as you want to create a Box and chose some Items, Java Server Faces will oops with "invalid value" on saving.
  Workaround: Override .equals() in Items-Clazz (see http://www.javapractices.com/topic/TopicAction.do?Id=17)
  Is there a more sophisticated solution?

• As soon as you restart your Server (or start a new Session an other way), one cannot view the Items on a box.
  Either Edit or View panel will fail lazy loading the Set<>.
  In Hibernate this will cause a "Lazy loading error"
  In OpenJPA this will cause a "Null Pointer Exception"
  In Datanucleus ... did not compile; not able to test
  and
  In Eclipselink - IT WORKS!!! (can anyone tell my why?)

=== Source Code

project --topLevelPackage org.example.esm --projectName ElementSetMockup
persistence setup --provider HIBERNATE --database HYPERSONIC_PERSISTENT
entity jpa --class ~.Box
entity jpa --class ~.Item
field string --fieldName name --class ~.Item
field string --fieldName name --class ~.Box
field set --fieldName myItems --type ~.Item
web jsf setup
web jsf all --package ~.jsf
exit