How to authenticate user via MS-CHAP or MS-CHAP v2 from EAPMakeMessage

Hello,

I'm developing eap.dll to add EAP-TTLS authentication functionality to
IAS.
I've already succeded in authenticating via EAP-TTLS + PAP & CHAP.
However, when I tried to invoke the authentication provider to
authenticate a user via MS-CHAP or MS-CHAP2 (set pEapOutput->Action =
EAPACTION_Authenticate,
and added Microsoft vendor specific attributes for those methods to
pEapOutput->pUserAttributes), it doesn't seem to work.

Does anyone know how I can solve this problem?

Thanks in advance.

-Moon