Disable Ctrl+Enter using VBA

Hi.

I have successfully restricted Paste, Ctrl+r and Ctrl+d in a workbook when a worksheet is protected using the following, but it is failing to disable Ctrl+Enter using both "^{ENTER}" and "^~", "":

Private Sub Workbook_SheetSelectionChange(ByVal Sh As Object, ByVal Target As Range)
If Not Sh.ProtectContents Then Exit Sub
Application.CutCopyMode = False
Application.OnKey "^d", ""
Application.OnKey "^r", ""
Application.OnKey "^{ENTER}", ""
Application.OnKey "^~", ""
End Sub

Have I done something wrong or is there another way to restrict Ctrl+Enter? (FYI I have tried using both "Enter" and "ENTER")

Thanks