Drive Setup 1.3 creates ProDOS partitions locked and not automountable by default. You can choose Customize Volumes and unlock the partition but there is no way to change the automount flag. Using Drive Setup 1.3 to update the driver on hard disks that have an older version of the Mac OS installed also marks ProDOS partitions as not automountable.
Workaround:- Initialize the drive with an earlier version of Drive Setup.
- Then install Mac OS 8 and click the Options button and uncheck the "update the hard disk drivers" option.