Logon Hours / Force Logoff Client

I'm running a Win 2k domain...classroom environment. I'm
trying to force a domain user's logoff on the client (Win
2k Pro) when the user's domain "Logon Hours" expire. The
user does not have access to network resources during
denied logon hours nor can the user log into the domain
during this time. However, if the user is already logged
in and the user's enters the "denied" logon hour period,
they remain logged on the client and Win 2k Server will
not force the user to logoff - on the client. I have
followed TechNet articles "Assigning Logon Hours", "Force
logoff when logon hours expire", article 318714 (...Group
Policy..."Automatically log off user when logon time
expires" and "Automatically log off user when logon time
expires - Locally"), and numerous other references and
hours of on-line research (more than I care to admit). The
user account is in builtin "Users" and the client is
in "Computers". The "Default Domain Policy" nor the new
policy I created will shut them down.

So, how do you force a domain user logging into a domain
to be logged off the client machine when their domain
logon time expires? Thanks in advance

Ed Maddox