VBScript EventSink: Why doesn't this work?

Hello,
I am trying out, what I thought to be, a simple event sink. I load a new message from an
existing file and want to replace the old incoming message with the new one.

Everything looks allright. sTempValue has the new subject, but when I receive the mail
its the old one. What am I missing here?

thank you,
Anders.



Sub ISMTPOnArrival_OnArrival(Msg, EventStatus)

      '// Load a new message
      Set fMsg = LoadMessageFromFile("c:\test.mai")

      '// Set old message to new message
      Set Msg = fMsg

      sTempValue = Msg.Subject '// Its the new one!!

End Sub


Function LoadMessageFromFile(Path) 'As Message
      On Error Resume Next

          Dim Stm2  'As ADODB.Stream
          Dim iMsg2 'As CDO.Message
          Dim iDsrc 'As CDO.IDataSource

      Set Stm2 = CreateObject("ADODB.Stream")
      Stm2.Charset = "ascii"
      Stm2.Open
      Stm2.LoadFromFile Path
            
      Set iMsg2 = CreateObject("CDO.Message")
      Set iDsrc = iMsg2.GetInterface("IDataSource")
      iDsrc.OpenObject Stm2, "_Stream"
            
      Set LoadMessageFromFile = iMsg2
End Function