How To Create Authentication Request Packet to pass as input to RADCLIENT

Hi, Does anyone know where can I find documentation about radclient? I am trying to figure out how to test EAP-MD5 using radclient. I want to use it to send Authentication Request packets to my AAA server where the authentication method is EAP-MD5. But I don't know how to create these packets (what attributes and values should be included). The EAP-Message attribute should be included but how do I emulate the correct value for it? Please help me with this. Thanks. Dana