Charlie, I'm not demanding anything from anyone. I gave a suggestion which I felt is valid and very useful. You chose not to incorporate it, and I'm sorry for wasting your time, sounding rude. If I knew how to fix the problem myself, I would have, but a lot of stuff in SME is not the same as in a standard CentOS installation, which is why I was looking for help, and got told that it can't be done. Then I submitted a feature request and was told it won't be done.
I accept that, and will happily get back to setting up a simple mail / file server with PPPoE on the same NIC as the local LAN manually.