rsync -b backup option on versions supporting HFS

OS X 10.4.6 (BSD)

I was using the 'standard' versions (i.e. non-HFS supporting) of rsync with the backup -b option so that I could do nightly incrementals.  This seemed to be running fine. Changes to existing backed up files got copied to the appropriate path(s) on the target.

BUDIR=myDirectoryName
time /usr/local/bin/rsync -a -b --suffix=# --backup-dir=$BUDIR /Users /Volumes/nephron

However, when I started using a version (2.6.0 protocol version 27) supporting HFS and choosing the extended attributes option, the sync works, but the copy to the backup directories doesn't work unless the path is already there.

time /usr/local/bin/rsync -eahfs -a -b --suffix=# --backup-dir=$BUDIR /Users /Volumes/nephron

That is, it appears that the non-HFS version creates the backup directory path if needed, but the HFS-supporting version does not automatically create the path.  However, if the path is already there, the non-HFS version does make a good copy.

Anyone else seen this?  Any suggested workarounds?

Thanks
je