Just set the EmailSME to point to the ISP's email and it works. Sort of. I think I'm being punished for trying to take one perfectly good piece of software and use it on two pieces of hardware.
I don't understand the bit about being punished. Could we stick to the facts?
I use the configuration I suggested at a number of sites - gateway server sets the internal server as the delegate and the internal server sets the gateway server as its ISP mail server. The gateway server can either deliver normally or can relay via the real ISP mail server. This is part of the SME Server design - no workaround should be required.
Your configuration won't work if the internal server cannot reach the ISP's mail server, as is often the case on tightly firewalled networks.
Is there a way to make sure the smtp proxy is turned off on the FirewallSME? I've turned it off in the GUI, but the qpsmtpd logs still show the passage of email when I send email out.
If the proxy panel doesn't disable it, please raise a bug. However, I think you should leave it on and configure as I suggested. That way LAN based viruses will be caught.