The only way to modify a ScreenTip for a toolbar command is to use a
little VBA. Since it isn't very intuitive, here's a macro that will
help you out:
Sub ChangeToolTip()
'Macro created by Beth Melton
'Nov 1, 2001
On Error Resume Next
Dim strbar As String
Dim bytNum As Byte
Dim strText As String
Dim strDText As String
Dim Choice As String
strDText = "Standard"
Do
strbar = InputBox("Type the name of the toolbar", , strDText)
strDText = strbar
bytNum = InputBox("Control Number: Starting with 1 " _
& "from the left of the Toolbar")
strText = InputBox("Type your ToolTip Text")
CommandBars(strbar).Controls(bytNum).TooltipText = strText
Choice = MsgBox("Do you want to add another ToolTip?", _
vbYesNo + vbQuestion)
Loop Until Choice = vbNo
End Sub