Have you tried one of those disks in the Mac? If the computer is newer than '87 it should be able to read it. If it doesn't than see if you can format the disk in HFS. If all else fails Norton Ghost might be able to format a floppy in HFS.
This link might help you figure out what filesystem you need the disk formatted in.
http://wapedia.mob...ernal_Disk_Drive#1 Hope this helps!