add a reference to Microsoft Visual Basic for Applications Extensibility" at run time

Hi
I've been on the WEB most of the day trying to figure this out. Is there code to "add a reference to Microsoft Visual Basic for Applications Extensibility" at run time.
I have this code that seems to require such a reference

' Modified from http://www.cpearson.com/excel/vbe.aspx
Public Sub DoModule8() 
Dim VBProj As VBIDE.VBProject
Dim VBComp As VBIDE.VBComponent
Dim CodeMod As VBIDE.CodeModule
Dim LineNum As Long
Const DQUOTE = """" ' one " character
Set VBProj = ActiveWorkbook.VBProject
Set VBComp = VBProj.VBComponents("Sheet1")
Set CodeMod = VBComp.CodeModule
With CodeMod
LineNum = .CreateEventProc("Activate", "Worksheet")
LineNum = LineNum + 1
.InsertLines LineNum, "Selection.OnAction = " & DQUOTE & "DoModule5"
.InsertLines LineNum, "ActiveSheet.Shapes(" & DQUOTE & "Button " & 1 & DQUOTE & ").Select"
.InsertLines LineNum, "Selection.OnAction = " & DQUOTE & "DoModule1"
.InsertLines LineNum, "ActiveSheet.Shapes(" & DQUOTE & "Button " & 2 & DQUOTE & ").Select"
End With
End Sub

And it results in this (after I set the reference manually)

Option Explicit
Private Sub Worksheet_Activate()
    ActiveSheet.Shapes("Button 2").Select
    Selection.OnAction = "DoModule1"
    ActiveSheet.Shapes("Button 1").Select
    Selection.OnAction = "DoModule5"
End Sub

Can I set the Reference pragmatically?
As always, your help is deeply appreciated.
John