How do I automate "Freeze Panes" in Excel?

When I freeze panes in Excel, the macro recorder gives me:

ActiveWindow.FreezePanes = True

To what object should I apply the .FreezePanes property, when using Automation?

This.oSheet contains a reference to the current sheet, with which I work all the time.

I also have a property This.oExcel, as a reference to Excel.

I tried:

This.oSheet.FreezePanes = .T. && The active sheet
* and:
This.oSheet.Parent.FreezePanes = .T. && The workbook

but both show error messages, in the sense that the property does not exist.

I also tried using This.oExcel.ActiveWindow, but it seems the property ActiveWindow doesn't exist.

TIA,

Hilmar