Das beschriebene Problem (und weitere) wurden mit DSM 4.1 Build 2647 behoben.
Fixed an issue where the folder and file names were case-sensitive when you access them via Windows File Sharing.
Fixed an issue where full backup was performed when it should be incremental backup. Amazon S3 users should apply this update to reduce the amount of data transmission.
Improved the NFS performance when mounted to VMware ESXi 5.1 servers.
Improved the AirPrint compatibility with iOS 6 devices.
Improved the compatibility with Internet Explorer 10.