How to automatically forward a user's all incoming and outgoing emails to his manager?

Hello,

SBS 2003

The client got a new employee and his manager would like to monitor all the new employee's  incoming and outgoing emails during the probation.

To forward the incoming emails, that is easy. I can do it from the user's properties on server. But how can i forward the outgoing emails without setting up a rule in the new employee's Outlook?

Thanks!

Jack