C++ RADIUS client code

I have a C++ program running on a Win2K Enterprise Server that currently
uses ADSI to
authenticate users of my application against an LDAP Membership

I need to begin authenticating these users against a RADIUS server also.

Can anyone tell me if ADSI can be used for authenticating against a RADIUS

server, or suggest another interface to facilitate RADIUS authentication
a pre-.Net C++ client application?