Apple II Hardrive on Mac

[ericc@phs.k12.ar.us (Eric Cronin)]

I have a 120 MB HD (Quantum in an external case) that I've been using with
a RamFast card in my Apple IIGS for several years now.  My use of that
computer had declined, and I'dlike to use the 50 or so unused MB as a Mac
HFS drive.  I partitioned and formated it like I wanted using the RamFast
utility, and GSOS shows it as a Mac Partition.  When I connect it to my
Centris 650 however, the only place I see it is in SCSIProbe, where it
appears the same (except size) as my internal drive.It won't mount, and
Apple SD HD or whatever doesn't recognize the drive...  What do I need to
do to get Mac OS to recognize it?  I'm running System 7.5 on a Centris 650
and System 6.0.1 on an Apple IIGS.  TIA for any help you can provide.