Why does this code not work (Change Sender Acct)?

I am using code copied at end of this message to try and change the "send
from" account. Code is based on Sue Mosher's Book example. For some reason
the Send From address does not change. I stepped through the code to check
and the Execute line gets run as expected. The problem appears to be that
the Send From Account does not get changed even throug the line is run. I am
using Outlook 2003.

Any help will be greatly appreciated.
Thanks in advance
Sanjay

Option Explicit
Const ACCT_TO_USE = "Someaccount"

Private Sub Application_ItemSend(ByVal Item As Object, Cancel As Boolean)
'How can we get the name of the account that will be used to send

Dim objInsp As Outlook.Inspector
Dim colCB As Office.CommandBars
Dim objCBAccounts As Office.CommandBarPopup
Dim objCBB As Office.CommandBarButton
Dim blnAccountFound As Boolean


Set objInsp = Item.GetInspector
Set colCB = objInsp.CommandBars
Set objCBAccounts = colCB.FindControl(ID:=31224)
Set objCBB = objCBAccounts.Controls.Item(1)

If Not objCBB Is Nothing Then
If objCBB.Caption <> ACCT_TO_USE Then
Set objCBB = Nothing
For Each objCBB In objCBAccounts.Controls
If InStr(1, objCBB.Caption, ACCT_TO_USE, vbTextCompare) > 0
Then
blnAccountFound = True
Err.Clear
objCBB.Execute

Exit For
End If
Next
End If

If blnAccountFound = False Or Err.Number <> 0 Then
Cancel = True
End If
End If

Set objInsp = Nothing
Set colCB = Nothing
Set objCBAccounts = Nothing
Set objCBB = Nothing

End Sub