Yeah, I put this on mantis before the beta. Anyway, you can actually map WASD to do the same thing as the arrow keys in the menus. If you go to 'View and Edit Controls' and click on the 'menu' tab there will be 'Cursor Down', 'Cursor Up', Cursor Left' and 'Cursor Right'. Just bind the keyboard alternative for these to the WASD keys and it should work.