I just spent a few hours reading up on the best way to connect my new 2T MyBook Live, NAS.
I first tried to mount the network hard disk manually, that when ok, except I couldn't get the permissions right.
I fiddled with fstab... couldn't get the permissions quite right... Installed smb4k... reading worked fine... no writing, even though the files are correctly chmodded...
So... then I fixed it in 1 minute...
Open Dolphin (file browser), click on network (in the places window). Add network folder -> Microsoft Windows Network Drive (even though the MyBook works with Lenny linux). Fill in the IP addres of your NAS (check this in your router table). And voila... done... omg... IT IS THAT EASY...