How many LAN ports are in the back of the DSL modem? 1 or 4?
Whice one of these is your model?
http://www.2wire.com/index.php?p=106Ok Found your model. Ya, you should be able to connect the LAN cable from any of the 4 LAN ports on the back of the 2wire too the WAN port on the back of the 4500.
Have you connected a PC directly to the DSL modem yet in this transparent state? You'll have to do the same thing by entering the PPPoE info I think to get internet if you directly connect a PC. This can be a test. The PC should pick up an IP address. Do you have a friend or neighbor that you can take the 4500 too and check a different connection?
It seems like this is a configuration issue between the DSL modem and 4500. Possible that the 4500 isn't being setup correctly with the PPPoE side of things. What happens if you just let the 4500 DHCP to the DSL modem?
Just some ideas for you to check after work.
I really dislike DSL ISP using these newer DSL router/modems. Makes things harder sometimes to use other routers that work better. I like just the stand alone modems.
The 4500 router should work great as I have helped my buddy in OK which he's on DSL and has the same issue, however his ISP was able to help him enter in the info on the 4500. So I know DSL with PPPoE works well on the 4500.
While your at work you can new an emulator for the 4500 here for informational purposes. I use this alot to help people:
http://www.dlink.com/support/faq/?prod_id=1457