From Custom1Node
 Role is an object with Name and Id fields
 
 @Override
  protected void saveToXml( Element element, XmlPersistContext xmlPersistContext )
  {
    super.saveToXml( element, xmlPersistContext );
    // now save role id & name
    Element roleElement = xmlPersistContext.addChildElement( "Role", element );
    xmlPersistContext.writeInt( null == role ? roleId : role.getId(), "id", roleElement );
    xmlPersistContext.writeString( null == role ? roleName : role.getRoleName(), "name", roleElement );
  }

  @Override
  protected void loadFromXml( Element element, XmlPersistContext xmlPersistContext )
    throws TransformerException, XmlException
  {
    super.loadFromXml( element, xmlPersistContext );
    Element roleElement = xmlPersistContext.getChildElement( element, "Role" );
    roleId = xmlPersistContext.readInt( "id", roleElement );
    roleName = xmlPersistContext.readString( "name", roleElement );
  }