Sure:
I have a async Web service working inside a Try block

Try
    Dim cb As New AsyncCallback(AddressOf callbackWs)
    Dim ar As IAsyncResult = myWS.BeginUpdater("ChainString", cb, myWS)
Catch x As Exception
    MessageBox.Show("Something happened")
End Try

Also I have a Callback routine

Sub callbackWs(ByVal ar As IAsyncResult)
       If ar.IsCompleted Then
           myWS.EndUpdater(ar)
        End If
End Sub

the problem is that when internet is unavailable or I unplug the cable or I
move the WS to another location the call to the WS does not get into the Try
block...It does nothing, so I dont know what happened.

ken