I found another work around solution if you don't need RAID function:
Remove one hard disk. Just put the un-formated disk into device
While you log into device, it will ask you to format it.
click ok, then the formation work.
After format successful, switch off the device and put another hard disk you already formated by DNS-321 before. then you can find these 2 hard disk works well.
conclusion:
FW 1.03 can do hard disk format successful when only one hard disk installed.