将Spring与XML配置文件一起使用时如何调用BeanFactoryPostProcessor.postProcessBeanFactory方法？

我有一个配置文件beans.xml：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans  
        http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-3.1.xsd
        ">


    <bean id="myBeanFactoryPostProcessor" class="com.ssll.MyBeanFactoryPostProcessor" />

    <bean id="myobj" class="com.ssll.MyFoo">
            <property name="realname" value="${dummy}" />
     </bean>
</beans>

这com.ssll.MyBeanFactoryPostProcessor是一个类：

public class MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor {  

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {  
        System.out.println("This is expected to called when the BeanFactory is created");  

        Properties p  = Config.getZooProperties();
        PropertyPlaceholderConfigurer cfg = new PropertyPlaceholderConfigurer();
        cfg.setProperties(p);
        cfg.postProcessBeanFactory(beanFactory);     
    }  

}  

但是postProcessBeanFactory从来没有打电话过，我错了，请帮忙。

我在这里做了一个小测试项目https://github.com/yujiaao/spring4test