Question about mac address auth / dot1x / vlan assignement.

I apologize if the subject is a little bit off topic. I have what seems now to be a classic scenario where I am trying to do mac address auth / vlan assignment using Windows XP / Cisco Catalyst switch running IOS / FreeRadius 1.0.5 After reading several posts on the mailing list about the subject, I was wondering if someone could clarify a specific point: Can the Windows XP built-in supplicant send the host mac-address as the username / password (during EAP-MD5 or EAP-PEAP) ? Thanks in advance for any tips. Best regards - Didier.