windows client (login + password)

Hello, I'm a new Radius Server user, yet I have slight problem with the configuration. I've managed to configure Radius so that it authorizes users from LDAP Oracle database. My problem is that I don't know how to configure Windows (client) so that it gets a new IP Address (after login with password from LDAP). Has anyone encountered the similar problem or is able to solve mine? -- Pawel volfen Malkowski