http://office.microsoft.com/en-us/outlook-help/automatically-forward-my-messages-to-another-e-mail-account-HA010227668.aspx

Forwarding in Outlook is done with 'Rules'.

Click on 'Out of Office Assistant'.

Note that Internet Explorer browser is require for full functionality.

In IE, browse to your Exchange server. With SBS, it's usually something like:

https://remote.yourdomain.com

1. Log in and select E-Mail.
2. Click on Options.
3. Select 'Rules' for forwarding.
4. Select 'Out of Office Assistant' for vacation messages.