The Wikkipedia entry has a procedure to mount them with Debian. So that might also save your bacon....
http://en.wikipedia.org/wiki/Western_Digital_My_BookFrom the article......
Internals
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Controller board for My Book World Edition
This drive runs BusyBox on Linux on an Oxford Semiconductor 0XE800 ARM chip which has the ARM926EJ-S core. In addition it uses a VIA Cicada Simpliphy vt6122 Gigabit Ethernet chipset, and a Hynix 32 Mbit DDR Synchronous DRAM chip. The webserver is the mini_http server, although older "bluerings" use Lighttpd. The drives of the World Edition are xfs formatted, which means that the drive can be mounted as a standard drive from within Linux if removed from the casing and installed in a normal PC.
The disk filesystems are also known to exist in a format created by linux multiple devices driver (Mdadm) which ultimately wraps an ext3 partition with some metadata that allows the inquiry of the position of the drive in a RAID set. Unfortunately, this makes mounting the drives outside of the enclosure a bit more complicated, it also requires a machine with a Linux (or possibly some other Unix) based operating system. For example, the best way to mount the drives on a Linux flavored operating system after they have been removed from the enclosure is to use the following set of commands (on Debian) for mirrored RAID 1 disks.
# modprobe md
# mknod /dev/md4 b 9 4
# apt-get install mdadm
# mdadm—assemble /dev/md4 /dev/sdb4
# mkdir /media/xyz
# mount /dev/md4 /media/xyz
# chmod -R 777 /media/xyz
The above set of commands assumes that the drives appear as /dev/sdb to Linux.
The following command set can be used for mounting a multidisk spanning RAID 0 set in Debian Linux:
# modprobe md
# mknod /dev/md4 b 9 4
# apt-get install mdadm
# mdadm -Cv /dev/md4 -l0 -n2 -c64 /dev/sdb4 /dev/sdc4
# mkdir /media/xyz
# mount /dev/md4 /media/xyz
# chmod -R 777 /media/xyz
The above set of commands assume that the drives appear as /dev/sda and /dev/sdb to Userspace.
With both sets of commands a utility such as Gparted can be used to determine which paths are relevant for a given setup.
Further details and support are available at the My Worldbook wiki.