For any interested I believe I have a solution to my problem.
My SME server will still have the domain name "mydomain.com"
The Windoze server will have 1 network card with a static IP address in the
internal LAN range behind the SME server and have the domain name "server.mydomain.com"
Using either OperVPN or RDP (Remote Desktop Protocol) and the right port configuration,
create a tunnel through the SME server to the Windoze server.
This should give us the remote access we need while still allowing us to be protected
byt the SME firewall since the SME server is in server/gateway mode
This is a link to some information on the subject
http://wiki.contribs.org/VPN_practical_tipsI Apologize If this was the wrong place for this question to be asked
Mike