It does do RADIUS, the guide is for the 2955 though so it shows a bunch of extra options.

The correct URL for the link above is

http://www.draytek.com/user/SupportAppnotesDetail.php?ID=204

The one posted omitted the www and doesnt work. Wish me luck, I've been on my own trying to get RADIUS working all night with Windows Server 2008 R2 and am not having a very good go of it so far.

Eesh, nope, that document sheds no light on how to get it working with Windows Server 2008 R2. It's purely client side config. Back to pounding my head against the wall.