BinaryImporter for Node extension

Hi, I'm trying to export/import an instance of HullNode which extends Node.

Importing throws :



SEVERE: Could not access constructor of class 'tools.visualization.HullNode'!

Some types need to have the BinaryImporter set up in a special way. Please doublecheck the setup.

2009-10-25 21:31:02 class com.jme.util.export.binary.BinaryImporter readObject(int id)



How I'm suppose to setup this class so that it can be property exported/imported.

See code below.

import com.jme.math.Vector3f;
import com.jme.renderer.ColorRGBA;
import com.jme.scene.BillboardNode;
import com.jme.scene.Geometry;
import com.jme.scene.Node;
import com.jme.scene.TriMesh;

public class HullNode extends Node
{
   private static final long serialVersionUID = -6210950473101174266L;

   private Vector3f center;

   private ColorRGBA colorRGBA;

   private Geometry hull;

   private BillboardNode labelNode;

   private Vector3f top;

   public HullNode()
   {
      super();
   }

   public HullNode(String label)
   {
      super(label);
   }

   public HullNode(String label, Vector3f center, ColorRGBA color)
   {
      super(label);
      setCenter(center);
      setColor(color);
   }

   public Vector3f getCenter()
   {
      return center;
   }

   public ColorRGBA getColor()
   {
      return colorRGBA;
   }

   public Geometry getHull()
   {
      return hull;
   }

   public BillboardNode getLabel()
   {
      return labelNode;
   }

   public Vector3f getTop()
   {
      return top;
   }

   public void setBillboardHull(TriMesh hull)
   {
      this.hull = hull;
      BillboardNode billboardNode = new BillboardNode(hull.getName() + "_billboard");
      billboardNode.attachChild(hull);
      billboardNode.setLocalTranslation(getCenter());
      attachChild(billboardNode);
   }

   public void setCenter(Vector3f center)
   {
      this.center = center;
   }

   public void setColor(ColorRGBA colorRGBA)
   {
      this.colorRGBA = colorRGBA;
   }

   public void setHull(Geometry hull)
   {
      this.hull = hull;
   }

   public void setLabel(BillboardNode labelNode)
   {
      this.labelNode = labelNode;
   }

   public void setTop(Vector3f top)
   {
      this.top = top;
   }

}



Thanks in advance for help!