Or, if you don't have access to stop/start services on the client, or you
don't have the reskit,  you could create a batch file with the following
lines:

net stop "ADSM Central Scheduler Service"
net start "ADSM Central Scheduler Service"

Or whatever your service name would be.  Create a script to copy that file
to each NT client (easiest) or, if you don't have access to the clients, you
can backup the batch file under a certain node, jigger around with a CMD
schedule to restore that file.  A possible command might be

dsmc res \\nodename\c$\filename c:\ -virtualnodename=nodename
-password=nodepassword
where nodename is the node you used to back up the file and filename is the
where nodename is the node you used to back up the file and filename is the
name of the batch file.  For this particular scenario, I would probably
register a whole new node to use because the password will be in everybody's
dsmsched.log.

Once the schedule is created and you test it on a test node, you can
associate all your clients with that schedule and wait for them all to run.
Once they all run, you'll have a batch file on every node that can stop and
start the schedule.  You can then create a CMD schedule to execute the batch
file.

Voila.

Needless to say, this has some pretty far reaching implications.

Alex