I'm no Outlook expert, but I think you can do this by declaring a new variable:
x As Long
then inserting:
Code:
'Get the Outlook account to use
With oOutlookApp.Session.Accounts
For x = 1 To .Count
If .Item(x).CurrentUser.Name = "Name_of_Account_to_Use" Then Exit For
Next
End With
before:
' Open the catalog mailmerge document
and changing:
.Send
to:
.SendUsingAccount = oOutlookApp.Session.Accounts.Item(x)