IN  PUNICODE_STRING pucRegistryPath,
  OUT PWSTR           *ppucLastElement,
  IN  int             *piLength

Routine Description:

    This routine is called by Nbt to find the last slash in a registry
    path name.


Return Value:

    The length of the path up to and including the last slash and a ptr
    to the first character of the last element of the string.