Monitoring Outlook Outbox?

Hi to all, I have some code in Outlook 2000 that monitors all emails sent by outlook and autosaves these emails to a variety of network locations depending on keywords in the message subject. The code is fired on the Application_ItemSend event. This all works very well and I have no problems.
The problem is that people also send files by right clicking files and selecting 'send to...mail recipient'. If they do this then the message appears in the outlook sent items but it does not fire the Application_ItemSend event.
Anyone have any ideas how I can monitoring this usage of email so that I can trigger some code in Outlook to save the sent message as above.
Thanks.....
AB