I've read that to boot a PowerPC Mac from a FireWire drive, the drive needs to be partitioned using Apple Partition Scheme. I've partitioned my new WD My Passport Studio drive twice, using Disk Utility with Apple Partition Scheme selected, and it will only boot Intel Macs. (When I boot a PowerPC Mac holding the option key, it doesn't see the FireWire drive.)

I need this bootable drive to repair an old eMac. Any ideas?