You could set the laptop up to using polling mode instead of prompted.. have
it poll every hour or something (default is 12 hours). then create a
schedule for the laptops that has a window of 12 hours during the day. When
a laptop is connected to the network it'll poll for it's schedule and if it
hasn't backed up for that day, start it's backup.

The only drawback I dislike about it is doing a backup puts a load on the
laptop and the users may become annoyed if the second they plug their laptop
in, it's slow and unusable until the backup finished. Perhaps if you tweak
the resourceutilization parameter or something along that line you can make
it run "nicer".

Gerald Wichmann
Senior Systems Development Engineer
Zantaz, Inc.
925.598.3099 (w)