The biggest added value (omitting the fact that you can use Hibernate and two databases) is Hibernate's Current Session context management with JTA. You do not have to take care about opening nor closing
Session as Hibernate will automatically bind them to the JTA transaction's lifecycle. You just have to make sure JTA transactions are properly started and ended.
You have to tell Hibernate where to get the BTM datasource via JNDI. Add a connection.datasource property and set its value to the JNDI location of your datasource:
Current session context
You have to set current_session_context_class to
Transaction factory class
When you use Hibernate via the JPA / EJB3 API (also known as Hibernate EntityManager) you should not set the
Transaction manager lookup class
There currently is a bug in BTM's connection pool that impacts all versions up to and including 1.3.2. You must set connection.release_mode to after_statement to workaround the bug (see Hibernate's documentation). If you don't, you might end up seeing BTM throwing exceptions and leaking connections.
This is bug BTM-33 which has been fixed in BTM 1.3.3.