You use Plinth Clips aka Kickboard Clips
http://www.screwmaster.co.uk/ekmps/shops/screwmaster/images/plinth_clip_500px_wm.jpg
Ceap from H/W or DIY store.
Screw bracket to kickboard and slide plastic clip in - they can move sideways to adjust to the legs so positioning is not much of an issue.
Good luck...
Peccavi
May 2009