Why do you need to do that? A copy is automatically saved in your Sent Items
folder. If you copy yourself then you end up with two emails instead of one.
If you wish to file certain Sent Items in another folder, you can specify
this in the Options of the email in question.
If that isn't the issue, please clarify what you're trying to achieve. What
you're currently suggesting is a duplication of work Outlook already does for
you automatically.
