Onkey method to call Label click event

I am using a userform where only labels are there.
Labels will be clicked and the even is fired.
I have also assigned Shortcut key to labels, but Pressing with ALT key, the code doesnot fire. So I have used Onkey method.
Even this is not firing label caption.
The codes are:

Private Sub Label5_Click()
MsgBox "You Clicked " & Label5.Caption
End Sub

Private Sub UserForm_Activate()
Application.OnKey "%s", "Label5_Click()"
End Sub

Private Sub UserForm_Deactivate()
Application.OnKey "%s", ""
End Sub

Label 5 caption is Select Company and accelerator is “S”

What’s the wrong going on? How can I use keyboard shortcut to fire label5 click event?