).As for as I know it's just a normal SATA cable.
http://www.overclockers.co.uk/showproduct.php?prodid=CB-024-AK&groupid=701&catid=48&subcat=196
Like most Cables and some External HDD's it wont make electric contact with the My Book, you need do this:
http://forums.overclockers.co.uk/showthread.php?t=17816228&highlight=cable+username_helmutcheese LOOK @ POST #10

Have you installed any Drivers for Windows, I think its a JMicron Sata Controler.
JMicron JMB36X RAID Controller Driver (Grab whatever your OS is).
http://support.asus.com/download/download.aspx?SLanguage=en-us&model=P5B Deluxe