I have the same problem on a physical W2K8R2 server. MSFT Premier Support said SDELETE would work, though testing has shown otherwise. I am using v1.61 of SDELETE. The output of sdelete /? seems to have changed a bit. I have used both switches -c and -z separately and together. My VV has zero detect enabled. I use IOMETER to fill of the disk, and then delete the file (which is too big for the recycle bin, so it deletes permanently). I have a 7400 running 3.1.2 MU2.
C:\Users\kwalters\Downloads\SDelete>sdelete /?
SDelete - Secure Delete v1.61
Copyright (C) 1999-2012 Mark Russinovich
Sysinternals -
http://www.sysinternals.comusage: sdelete [-p passes] [-s] [-q] <file or directory> ...
sdelete [-p passes] [-z|-c] [drive letter] ...
-a Remove Read-Only attribute
-c Clean free space
-p passes Specifies number of overwrite passes (default is 1)
-q Don't print errors (Quiet)
-s or -r Recurse subdirectories
-z Zero free space (good for virtual disk optimization)
I will log a call with HP and ping MSFT again and see if they can come up with anything. I am not worried about the whole %Virtual > 100, but I would like to reclaim unused space when host drive utilization changes dramatically. *