I want to turn my BM server into a HTTP cache only server as I'm
installing a Cisco ASA to do VPN peer connection with some vendors and
after many attempts we couldn't get it to work. So I want to know what I
need to do to get it to just work as a Proxy Server.

I'm thinking I need to do the following:
Inetcfg - Disable the public interface which will disable the NAT
Inetcfg - Add a default route/gateway to the inside interface of the
Cisco ASA
NWADMIN - Turn off Filtering and VPN
Reboot

Is there anything else that I would need to do?

Thanks in advance,
Tim