I've tried the following in that mode:
2-wire 2700hg... fairly easy to do with the version i have.
netgear dg834g v3 and v4... trivial to do via hidden web page.
speedtouch 585v7... really hard to do right, but possible.
billion bipac 7700n ... easy-ish.
-- gyre --
plusnet via Draytek Vigor 2920 and Billion BiPAC 7700N (bridged)