请教一个关于多数据源的分布式事务问题？

－－－－－－－数据源 1 的hibernate.cfg.xml－－－－－－－－－－－－－－－－
<?xml version="1.0" encoding="utf-8" ?>
!DOCTYPE hibernate-configuration
 PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN"
 "http://hibernate.sourceforge.net/hibernate-configuration-2.0.dtd">

<hibernate-configuration>
<session-factory >
<property name="connection.datasource">TestDB</property>
<property name="transaction.factory_class">net.sf.hibernate.transaction.JTATransactionFactory</property>
<property name="transaction.manager_lookup_class">net.sf.hibernate.transaction.WeblogicTransactionManagerLookup</property>
<property name="dialect">net.sf.hibernate.dialect.SQLServerDialect</property>
<property name="hibernate.connection.provider_class">net.sf.hibernate.connection.DatasourceConnectionProvider</property>
<property name="hibernate.jndi.class">weblogic.jndi.WLInitialContextFactory</property>
<property name="hibernate.jdbc.fetch_size">100</property>
<property name="hibernate.jdbc.batch_size">50</property>
<property name="show_sql">true</property>
<mapping resource="test/Addressbook.hbm.xml" />
</session-factory>
</hibernate-configuration>

－－－－－－－数据源 1 的hibernate.cfg.xml－－－－－－－－－－－－－－－－

－－－－－－－数据源 2 的hibernate.cfg.xml－－－－－－－－－－－－－－－－
<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE hibernate-configuration
 PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN"
 "http://hibernate.sourceforge.net/hibernate-configuration-2.0.dtd">

<hibernate-configuration>
<session-factory >

<property name="connection.datasource">txyyDB</property> 
<property name="transaction.factory_class">net.sf.hibernate.transaction.JTATransactionFactory</property>
<property name="transaction.manager_lookup_class">net.sf.hibernate.transaction.WeblogicTransactionManagerLookup</property>
<property name="dialect">net.sf.hibernate.dialect.SQLServerDialect</property>  -- dialect
<property name="hibernate.connection.provider_class">net.sf.hibernate.connection.DatasourceConnectionProvider</property> 
<property name="hibernate.jndi.class">weblogic.jndi.WLInitialContextFactory</property>
<property name="hibernate.jdbc.fetch_size">100</property>
<property name="hibernate.jdbc.batch_size">50</property>
<property name="show_sql">true</property>
<mapping resource="test/Txyy.hbm.xml" />
</session-factory>
</hibernate-configuration>

－－－－－－－数据源 2 的hibernate.cfg.xml－－－－－－－－－－－－－－－－

－－－－－－－－－－－例子程序源代码－－－－－－－－－－－－－－－－－－－－－－－
package test;

import net.sf.hibernate.*;
import net.sf.hibernate.cfg.Configuration;
import java.io.*;
import java.util.*;
import util.NamingContext;
import javax.transaction.*;
import javax.naming.*;

public class MyTest {

    public static SessionFactory sf1

    public static SessionFactory sf2;

    static{
        try{
            Configuration config1 = new Configuration().configure("/hfcfg/hibernate.cfg.xml");   // 创建数据源1的Config对象
            Configuration config2 = new Configuration().configure("/cfg/hibernate.cfg.xml");   //  创建数据源2的Config对象

	// 根据配置创建对应2个数据源的SessionFactory对象
            sf1= config.buildSessionFactory();
            sf2 = config1.buildSessionFactory();

        }catch(Exception e){e.printStackTrace();}
    }

    MyTest(){}

    // 主要的业务测试方法，分别对两个数据源中的两张表执行插入操作，并置于同一事务下		
    public List test() throws Exception{

        Context ctx = util.NamingContext.getInitialContext();
        UserTransaction tx =(UserTransaction) ctx.lookup("javax.transaction.UserTransaction");

        if(tx != null) {
            System.out.println("获取UserTransaction实例 = " + tx.toString() + "--" + tx.getClass());
        }

        // 事务开始
        tx.begin();
        Session s1 = sf1.openSession();	
        Session s2 = sf2.openSession();

        List addressList = null;
        try{

           addressList = session.find("from Addressbook as c order by c.name asc");

            addressbook ar = new Addressbook();
            ar.setAddress("gz");
            ar.setName("hf");
            ar.setPhone("111");
            s1.save(ar);

            Txyy ty = new Txyy();
            ty.setYyms("test");
            s2.save(ty);

            for (Iterator it = addressList .iterator(); it.hasNext(); ) {
                System.out.println(((Addressbook) it.next()).getName());
            }

        tx.commit(); // 事务提交

       }catch (Exception e) {
           if (tx != null) {
                System.out.println("||||------事务回滚了--------||||");
               tx.rollback();
           }
           throw e;
       }finally {
           s1.close();
           s2.close();
       }
        return addressList;
  }
}

javax.transaction.UserTransaction tx = new InitialContext().lookup("javax.transaction.UserTransaction"); 
Session s1 = sf.openSession(); ... s1.flush(); 
    s1.close(); ... 

Session s2 = sf.openSession(); ... 
    s2.flush(); 
    s2.close(); 

tx.commit();