Are you just trying to format your hard drive for Amiga use?
I recall a disk called something like 'HD Toolkit' which was available from many PD houses and worked kind of like a windows startup disk and allowed you to format and partition your drive.
An easier option may be for you to create an Amiga bootable floppy with 'Format' on it. This is easier than taking your Amiga apart removing the HD and then putting it back in.
You can create an 'Emergency Disk' with 3.9. If you could find these disk images on the net and put them onto 720k floppy you may find them very useful.
