I've used the scripts / binaries and howto's from
www.adsl4linux.nl, and everything works just fine.
The server boots, at some moment the adsl connection becomes active, and then 2 events happen, the second event is /etc/e-smith/events/ip-up/S20email-ipup. The other event is ip-up, perhaps the first one is invoked by the second one.
The e-smith/Mxstream howto used to be on
www.e-smith.nl, but that website seems to be down a lot due to dns problems. Use the Google cache (search for e-smith adsl mxstream howto) to view the howto. Perhaps that howto brings the solution.