It might be an option to use an existing slice and copy (not rename) it to replace the missing slice, but it doesn't make any sense to rename them!? In your case the s011 slice is smaller than the others, which means the metadata in this file is different and it cannot be used to replace one of the other slices.
All you should have done is to just copy e.g. Windows 7-s010 to Windows 7-s009. Although this will most likely cause data corruption in the guest OS itself, it should at least allow you to make the virtual disk and extract important files. If you are lucky you may also be able to start and fix (e.g. using chkdsk) the Windows 7 VM. In any case, ensure you backup all the files prior to modifying anything!
André