Hi Numbergood,
I didnt persue this any further. I am quite keen to keep my SME's as close to "production" as possible and only use addons that have some sort of "higher power" knowledge attached to them. I can certainly find my way round SME for the greater part but I am NOT a linux guru and very much on a learning curve for the intracacies. To hack the distro to incorporate this in my situation would be suicide. If I ever find enough time I might try it for the hell of it but that doesnt seem likely in the near future.
As was pointed out, ADSL ethernet device are very readily available and also very cheap. In NZ, many ISP are giving away these devices and they are very respectible and fully featured at that. (full port forwarding, DHCP spoofing etc)
My "frog" is back on the shelf and at some point I know I will need to build an ADSL firewall only so I will revisit at that time and integrate into an IPCop setup where I have already used it and am very comfortable.
Rgds
Peter