Hello, Is possible to save and load to a file only the text shapes of a diagram?

I tried to do with the filter option of the persistencymanager savetofile method, but I am not sure how to use it.

Dim manager As New NPersistencyManager()

Dim filtro As New NSerializationFilter

Dim valores As New ArrayList

valores.Add(GetType(NTextShape))

filtro.SetSerializedTypes(valores)

manager.PersistentDocument.Sections.Add(New NPersistentSection("Drawing", NDrawingDocument1))

manager.SaveToFile(fichero, Nevron.Serialization.PersistencyFormat.XML, filtro)

These saves all the diagram not only the ntextshape objects.

Regards,

Laura