My ISP is using MSCHAPv2 for VDSL connection authentication. I saw that my SRX uses CHAP-MD5. Is it any chance to force it to use MSCHAPv2 ?
What version of Junos are you running? I did an install for a customer before Christmas and had all sorts of issues getting the SRX to connect to the ISP. After upgrading it to 12.1X45 used the ADSL wizard I was successfully able to connect.
I have 12.1X45.5. Also created a case in JTAC for this issue. It would be strange if SRX is not able to do MSCHAPv2 auth with pppoe. It can do it whit auth profile and radius authentication.