If your ADSL conction is popping up as a PNP device then chances are it was configured with port forwarding during server setup. Problem is is that the auto config does never seem to hold the settings very well (from experience).
Log into the device and configure your port forwarding to the server. Specific to RWW is ports 1723 and 443. I suggest your port forward 80 as well as RWW needs a certificate to function properly on 443 and I dont know that you have sucessfully implented that step.
I would turn off PNP in the ADSL modem.\
If you are using exchange dont forget port 25\
If you are using internet accessible sharepoint, add 444 (TCP)
For security reasons, make sure to change the default supplied password in the Modem.
If you are not paying per connection, turn on keep alive (different modems label this defferntly) but the basic idea is that it will auto ping a website every 5 minutes or so to keep the connection up. Technically, PPOe is considered dial up and sometimes the modems are configured to demand dial (connect as needed).
Do you have a static IP? If not register with DNSExit or something.
If all works okay, next step is to impliment your certificate and ssl. repost and I can help you with this too.
--ElaborateIT
