When you connect to the system using the web interface and select Advanced>Network Access, do you see both disks in the SMB List? If so, in the Users/Groups column are the values the same for Volume_1 and Volume_2? Also, is the Read/Write box at the top of the SMB List section contain a check mark?
I do not have a Windows machine available so I can not run the Easy Search Utility. It was my impression that the ESU helped you find the DNS-323 but after that ESU and the GUI interface were the same. Unfortunately, without a new disk I can't duplicate your experience.