Exchange 2000, OWA via Apache Rev. Proxy

I am trying to get Exchange OWA working in a Windows 2000 environment with Apache Reverse Proxy running on a linux box outside a firewall.
It appears that the apache/linux box is able to authenticate to the exchange server inside the firewall, it then splits the screen to display the owa information but then just dies with a server not found error.
Has anyone ever been able to get OWA working using Apache Rev Proxy, (the firewall is not an issue because I have it completely open between the server and the apache/linux box).
I am wondering if the only way to get it to work is to use a Front-End server (which I believe requires the enterprise edition of exchange) which then gives the iis server the exchange components neccessary to talk to the exchange back end.
Thanks for any and all help.