Extending XMLBeans Generated Classes in Java

Question

Does anyone know how to extend an XML beans generated class in Java so that the extended class can be used?

I am really struggling! FlightImpl is the implementation of the generated classes. When i use the super constructor argument schemaType() the code compiles fine. The problem arises that when i then try to refer to this object for a method native to FlightImpl - i get a an 'unknown source' exception.

Does anyone know what is causing this Exception underneath?

at org.thinkresearch.dave.xml.recall.impl.FlightDocumentImpl$FlightImpl.getCallsign(Unknown Source)

public class VisualFlight extends FlightImpl{


 private FlightVisualState flightVisualState;
 private FlightControlState flightControlState;
 private ArrayList<Trajectory>replayTrajectories;
 private ArrayList<Trajectory>simulatedTrajectories;
 private Trajectory currentTrajectory;

 public VisualFlight(FlightImpl flight) {
  super(flight.schemaType());
 }

 public void initialize(IRerunModel model) {
  flightVisualState = new FlightVisualState((IRerunFlightOptionsModel)model);
  flightControlState = FlightControlState.RECORDED;
  initializeTrajectories(model.getRecordedTrajectories());
 }

 private void initializeTrajectories(List<RecRunTraj> recordedTrajectories) {
  for (RecRunTraj traj : recordedTrajectories){
   if(traj.getRecRunTrajReferToCallsign().getCallsign()
               .equals(VisualFlight.this.getCallsign()))
    replayTrajectories.add(new Trajectory(traj));
  }
 }

 public FlightVisualState getFlightVisualState() {
  return flightVisualState;
 }

 public FlightControlState getFlightControlState() {
  return flightControlState;
 }

 public ArrayList<Trajectory> getReplayTrajectories() {
  return replayTrajectories;
 }

 public ArrayList<Trajectory> getSimulatedTrajectories() {
  return simulatedTrajectories;
 }

 public Trajectory getCurrentTrajectory() {
  return currentTrajectory;
 }