From what I understand, all Qwest branded modems should auto-detect the PPPOE username/password as you open a web browser as long as you have the DSL phone #. At least all the modems i've setup for family members/myself have.. This is in former Qwest territory though.
I do remember doing what you mentioned, but something must have changed, because I did hard set on my modem & it detected what speed I had & then it said to go to this other page & enter in my username & password.
Not sure why they changed it or if it just didn't like me