How do I generate auto response in Exchange 2003 / Outlook 2007?

I have an employee that is leaving, The new employee will be filling her slot. I want the old employee email to automatically repsond when someone emails that ex-employee.

Something like..The email address you are trying to send to is no longer and active email account. Your email has been forward to xxx@xxxx.com please update your records.

I trined using the out of office assistant, which works but only works once per sender. I want it to work every time someone sends the ex-employee a message.

I tried the rules but for the rules to work Outlook has to be running for the ex-employee.

What is the best way of setting this up?