New one: Securing an HTTP server

[Firewalls <Firewalls () exchange ware net>]

Turns out the ftp is out and HTTP is in. 

Basically we want to server confidential documents to end user internet
customers.

SSL encryption will be used, however we need to pull the documents off a
"server" inside
our corporate network. 

I'd like recommendations on the "best way" to serve these files without
exposing the inside
server.

Here's a simple drawing of what we are considering:

User ----> Public HTTP Server (colocation provider)----> Private Network
---> Cisco PIX ---> Corporate HTTP Server

Specifically I'm looking for recommendations on the proxy code for the
public server, Unix or NT is acceptable.

TIA,