Calling a client function from an ActiveX exe server

Is it possible to pass a callback function pointer from a client to
an ActiveX exe server, and later having the server calling the client callback function?

This is what I would like to do:

'// === Client appl ===
Private objServer as Object
Sub AnySub()
Set objServer = CreateObject("MyServer.Notifier")
objServer.Subscribe(AddressOf ClientCallback)
End Sub

'// this sub is placed in a module in the client appl
Sub ClientCallback()
End Sub

'// === ActiveX exe server appl, Notifier class ===
Public Sub Notifier(lngFunctionPointer as long)
'// Here I would like to call the client function (ClientCallback in
'// this example) using lngFunctionPointer , how?
End Sub

Ups...the name of the server sub should of course be "Subscribe" and not "Notify"...