MAC-auth only to AP needs a little guidance.

Hi all. Im just got radius with user/password to work with my firewall and i just love it! Now i would like to make it rock with our airport basestations to. I only want MAC-authentication, isearched everywhere but i cant find a single example for this , without EAP/TLS. I tried: <MAC-ADDR> "shared secret" as more or less a panic try but of course it didnt work. If anyone could just give me an example or hint where to find some nice info about it would make me happy. Thx p