Hi,
   There may be another option to resolve this issue, and I'm sure
there will be some on the list that will be interested.  The Apple 
MkLinux project has resulted in a tool for solving this problem 
AND using the standard HD SC disktool with "foreign" disks on
the Mac.  This works only with HD SC 7.3.5 to my knowledge.

    The MkLinux distribution (DR 2.1) includes the proper version,
and its available on the net from their site.  There is also a "patch"
for that specific version (it works only on that version as far as I
know) but that is not provided and must be ftp'd from:
     www.euronet.nl/users/ernstoud/patch.html

You also need ResEdit to alter one byte.  See the publication by
Apple, MkLinux: Microkernel Linux for the Power Macintosh, 
page 16-17.

Since this project and publication is supported by Apple, I expect
it is at least quasi-official.  I've used this modified HD SC for months
including using it to setup the partitions on my old Mac's for NetBSD.

Paul