Setup Exchange 2007 ActiveSync web application on a separate server

I have Exchange 2007 installed on SBS 2008. I also run a web server on the network. I only have one static IP and all traffic trough port 443 is routed to the webserver.

I would like to publish the ActiveSync application externally. If i temporarily route 443 traffic to the SBS then it is published (along with owa and everything else which i don't want).

Is there a way to host the ActiveSync application on the web server (Server 2008 with IIS7) or to get it to route traffic meant for the ActiveSync application?

I have tried creating a site on the webserver which uses the ActiveSync folder on the SBS but that does not seem to work.

Thanks,

Michael