Julie,
I will have the same "problem" in the near future.
Our database admin wants me to do online backups during the week
and an offline backup on saturday.
I will use preschedulecmd and postschedulecmd to start a REXX procedure
(REXX is a simple language available for all platforms for free) which
checks the
day of  the week and does the database shutdown and restart accordingly.
My goal is to keep administration simple (only one node and DSM.OPT) and
the
point of control central at the ADSM server (no scheduler at the
client).
I have not tested this yet but I hope it will work as desired.
Hope this helps
Kind regards

Thomas Rupp