yasemin 0 Newbie Poster

Hello!
I have an exchange 2000 server, a server with Cisco Secure ACS, and a cisco catalyst 2950 switch. I am trying to set up an authentication system. From what I understood, when a user tries to get authentication to log on to the network, first the internal list of users in the cisco secure acs will be checked. if that fails, the cisco secure acs will try the database (external database) configured in the unknown user policy and check whether authentication can be given to that user or not. if successful, the user is added to the cisco secure acs internal database....

How can I get the users in my exchange 2000 server to be put into the external database of my cisco secure ACS server? (so that I can check for authentication) I have been trying to solve these problem for weeks now!! Any help is greatly appreciated!!!!!!!!!
-Yasemin