title: adding an annotation to a JAXB binding class from a schema
body: <p>Hi stackoverflow world,</p>
  
  <p>I want to specify in a XSD that a specific element can be used as a XmlRootElement by JAXB.</p>
  
  <p>I know how to add the annotation to the generated class: what I want to do is to specify that a element can be generated as a root element before the code generation. </p>
  
  <p>I use external JAXB customizations (.xjb files).
  The purpose is here to not modifying the schemas (as they are defining standards).</p>
  
  <p>Anybody knows how do that?
  Thanks!</p>
  
  <p>NJ</p>