SBS Server 2003 and Vista Home Edition – VPN Gateway – Setup Exchange

We have just created a VPN Gateway (Netgear FV338) from the office SBS Server 2003 (which has Exchange 2003 on it) to the owners home office computer (Vista Home)(Netgear FV318). It connects perfectly, we can access documents & other data, but can’t configure the Outlook 2003 on their Vista Home to find Exchange 2003 on the server. There are some public folders in Exchange that he needs access to.

What’s the secret?