[AccessD] A2K: Undo a Parent from a sub

Hello all

The standard Me.Undo will perform a record level undo if activated from a form. Excellent
How do I perform a Me.Undo (to the parent) from a sub form?

Eg 
Me.Parent.Undo doesn't work
Me.Parent.Form.Undo doesn't work

dim strFormName
strFormName = Me.Parent.Form.Name

Forms(strFormName).Undo doesn't work

Any suggestions?

Darren