NTSTATUS
DiskRegistryAssignDblSpaceLetter(
  IN  PWSTR CvfName,
  IN  WCHAR DriveLetter
  );

Routine Description:

    This routine sets up the values in the registry that will be used
    to cause DoubleSpace volumes to mount on boot.

Arguments:

    CvfName - the NT device name for the DoubleSpace volume.
    DriveLetter - the desired drive letter

Return Value:

    NT status indicating success or failure