session bean + hibernate 怎么整合

现在要在一个会话bean中调用基于hibernate的持久层，请问如果控制事务？相关代码如下 
persistence.xml 
<persistence-unit name="jbpmUnit" transaction-type="JTA">  
      <provider>org.hibernate.ejb.HibernatePersistence</provider> 
       <jta-data-source>java:/JBPMAFISDS</jta-data-source>  
  <properties> 
<property name="hibernate.ejb.cfgfile" value="/hibernate.cfg.xml"/> 
</properties> 
</persistence-unit> hibernate.cfg.xml <property name="connection.username">jbpm</property> 
<property name="connection.url">jdbc:oracle:thin:@localhost:1521:orcl</property> 
<property name="dialect">org.hibernate.dialect.Oracle9Dialect</property> 
<property name="myeclipse.connection.profile">OracleConn</property> 
<property name="connection.password">hellobpm</property> 
<property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property> 
<property name="transaction.factory_class">org.hibernate.transaction.CMTTransactionFactory</property> 
<property name="hibernate.transaction.manager_lookup_class">org.hibernate.transaction.JBossTransactionManagerLookup</property> 
<property name="hibernate.cache.provider_class">org.hibernate.cache.HashtableCacheProvider</property> 
<property name="hibernate.session_factory_name">java:/JBPMAFISDS</property> 这是主要的两个配置文件，然后就是在一个会话bean中调用dao层的几个方法，结果发现发出了sql语句，但是数据库中没有任何记录 
希望大家能够帮忙啊 急