Using a clean install of Embedded x64 versions 775, 804 and 847, I'm able to import all of my disks (see Disk Management.png) and the Format list shows them all correctly (see Format.png). When I restore my original configuration (Backup/Restore -> Restore Configuration), the Fujitsu drive appears in Disk Management but is not visible in the Format or Mount Point lists. This is confirmed when looking at the disk_init.php source. I've checked my configuration XML and can't see anything obvious which would cause this. I noticed on the forum that a number of users have mentioned the same, however there didn't seem to be a conclusive answer hence why I've logged it here as I believe it may be a bug.
If anyone would like to view my config XML, please let me know and I'll be happy to provide it.