Formatting the Western Digital 1TB external Firewire disk with the Apple disk utility leads to errors when using Mac OS X (Journaled) instead of FAT32 format. This can be easily solved by using the non-GUI version to create the correct partition:
First start with „diskutil list“ in Terminal and determine the correct name of the harddisk. On my Mac mini the result is:

/dev/disk0
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *111.8 Gi disk0
1: EFI 200.0 Mi disk0s1
2: Apple_HFS Mini_Boot 111.5 Gi disk0s2
/dev/disk1
#: TYPE NAME SIZE IDENTIFIER
0: FDisk_partition_scheme *931.5 Gi disk1
1: Apple_HFS 931.5 Gi disk1s1

Be careful to pick the right disk in the next step since it will be erased:

diskutil eraseDisk „Journaled HFS+“ desiredvolumename disk1

Started erase on disk disk1
Creating partition map
Formatting disk1s2 as Mac OS Extended (Journaled) with name FW_Mini
[ + 0%..10%..20%..30%..40%..50%..60%..70%..80%..90%..100% ]
Finished erase on disk disk1
Finished partitioning on disk disk1

That’s it!