Map Tiles Class GlobalSettings.ApplicationCallback in VB.Net

Hi All,
I am curious to see if their is any GlobalCallback for the Map Tiles Class. I can get the global callback to function correctly on loading shapes and can see the progress and loading messages,but dont see any activity on loading slow or missing map tiles.
Is there a certain way to do this in VB.net? Have tried all the following commented options on the map loading event to no avail.
Does the built in ICallback know anything about the events in the Tiles Class?
Again, any help appreciated.
Regards
Terry

'Ax_Map1.Tiles.GlobalCallback = Me
 'Ax_Map1.GlobalCallback = Me
 'Dim t As Tiles
 't = Ax_Map1.Tiles
 't.GlobalCallback = Me

Dim gs As New MapWinGIS.GlobalSettings
gs.ApplicationCallback = Me
gs.CallbackVerbosity = MapWinGIS.tkCallbackVerbosity.cvAll

Private Sub ICallback_Progress(KeyOfSender As String, Percent As Integer, Message As String) Implements ICallback.Progress

    Debug.Print(Message & ": " & Percent & "%")

End Sub

Private Sub ICallback_Error(KeyOfSender As String, ErrorMsg As String) Implements ICallback.Error

    Debug.Print("Error reported: " & ErrorMsg)

End Sub