Nas-Port-Type Attribute

Hi, I put this line in the users file ( DEFAULT NAS-Port-Type == "PPPoEoA", Auth-Type = Accept ). I just want any user with that NAS-Port-Type to be accepted, but the RDAIUS doesn't start at all when i do this !! I know that this Value ( PPPoEoA ) is not a standard NAS-Port-Type value, but what is the problem ?? Is there any limitation on using a non standard value ?? regards, amr ali