Win Server 2008 R2 iSCSI Target 3.3 error creating a VHD

I started evaluating iSCSI Target 3.3 for selling purposes in various scenarios. I have a bad issue that I cannot explain. My set is the following: HP Proliant Microserver with 2 SATA RAID1 volumes, first is 250GB (C:), second is 3TB (D:). OS is Win 2008 R2 Std EN-US with SP1 + iSCSI Target 3.3. Server is joigned to my AD domain. When I create a VHD on the C: drive, it works fine and I can connect any iSCSI Initiator client to the target with problem. But if I try to create a VHD on the D: drive, the operation fails with error message: "The virtual disk cannot be created on the selected volume. The parameter is incorrect." Windows Application log show the following entry: "The Microsoft iSCSI Software Target service could not create the virtual disk using device D:\test.vhd. The operation failed with error code 0x80070057.Source: WinTarget, Error, Event ID: 13". If I create the VHD on the C: drive, move it to D: then try to import it, same problem. I double checked a lot of things (VHD is more than 300 MB, NTFS permissions, and so on) and I cannot find any reason why this occurs. Any idea? Thanks you all.