We're using WAS 6, here's the transaction section of the hibernate configuration xml:
Code:
<property name="jta.UserTransaction">java:comp/UserTransaction</property>
<property name="TransactionStrategy">org.hibernate.transaction.JTATransactionFactory</property>
<property name="transaction.factory_class">org.hibernate.transaction.JTATransactionFactory</property>
<property name="TransactionManagerLookup">org.hibernate.transaction.WebSphereTransactionManagerLookup</property>
<property name="transaction.manager_lookup_class">org.hibernate.transaction.WebSphereTransactionManagerLookup</property>
<property name="TransactionManagerLookupStrategy">org.hibernate.transaction.WebSphereTransactionManagerLookup</property>
<property name="transaction.auto_close_session">true</property>
<property name="transaction.flush_before_completion">true</property>
Also, if you start getting access problems on deployment, then put a was.policy file in your deployable unit with suitable access setting.