I can't seem to add more than one test to the schedule list. It is located under Management > Disk Management > S.M.A.R.T. Test. I can't seem to find the answer in the forums. I am currently running firmware version 2.00.
I saw this in another thread, but no answer was given.
http://forums.dlink.com/index.php?topic=10487.msg62029#msg62029