如何正确使用Jackson的JaxbAnnotationIntrospector ?

I'm able to generate the XML I want using @JacksonXmlProperty annotations with the default mapper configuration. But my classes are generated by maven-jaxb2-plugin and already have the @XmlAttribute annotations. When I try using the JaxbAnnotationIntrospector it serializes the attributes as child elements. What am I doing wrong?I'm able to generate the XML I want using @Jack