xstream.registerConverter(new ElementConverter());
xstream.alias("person", Person.class);
Dom4JDriver driver = new Dom4JDriver();
Person person = (Person) xstream.unmarshal(driver.createReader(new StringReader(xml)));
assertEquals("jason", person.firstName);
assertEquals("van Zyl", person.lastName);
assertNotNull(person.element);
assertEquals("bar", person.element.element("foo").getText());