IGH_PreviewData crash

Hi!

I'm working in a new GrassHopper plugin using C++/Cli language

I create a new GH_Goo type and I need to preview it.

The code compiles and link perfectly, but when GrassHopper is loading from Rhino I have this message

"The method 'DrawViewportWires' in type '....GhVaWall'  doesn't have an implementation"

¿Any idea?. If I don't implement the IGH_PreviewData interface it works fine.

If I implement the IGH_PreviewObject interface in any GH_Component subtype I have not any problems.

Thank's!!!

public ref class GhVaWall : public IGH_GeometricGoo, public IGH_BakeAwareData, public IGH_PreviewData
{
     ... 

property BoundingBox ClippingBox { virtual BoundingBox get(); }
virtual void DrawViewportWires(Rhino::Display::RhinoViewport ^,Rhino::Display::DisplayPipeline ^,System::Drawing::Color,int);
virtual void DrawViewportMeshes(Rhino::Display::RhinoViewport ^,Rhino::Display::DisplayPipeline ^,Rhino::Display::DisplayMaterial ^);

}

/*---------------------------------------------------------------------------*/

BoundingBox GhVaWall::ClippingBox::get()
{
GhVaUtil_debug_str(L"GhVaWall::ClippingBox", 0, true);
return BoundingBox();
}

//----------------------------------------------------------------------------------------------------

void GhVaWall::DrawViewportWires(Rhino::Display::RhinoViewport ^viewport, Rhino::Display::DisplayPipeline ^pipeline, System::Drawing::Color col, int thickness)
{
GhVaUtil_debug_str(L"GhVaWall::DrawViewportWires", 0, true);
// Test
pipeline->DrawArrow(Line(Point3d(0,0,0), Point3d(10,10,10)), col);
}

//----------------------------------------------------------------------------------------------------

void GhVaWall::DrawViewportMeshes(Rhino::Display::RhinoViewport ^viewport, Rhino::Display::DisplayPipeline ^pipeline, Rhino::Display::DisplayMaterial ^material)
{
GhVaUtil_debug_str(L"GhVaWall::DrawViewportMeshes", 0, true);
// TO DO
}