The picture above shown all my WD External Devices.
What if I want to Backup my My Book Studio Backup Drive into another My Book Studio (or other WD External) Backup Drive inside WD SmartWare?
Instead of using common ‘Copy & Paste’ via Finder / Win Explorer, so I will obtain the same file structures and metadata.
Or… If I want to Backup my Macbook Pro into 3 separate WD External Drives connected. (simultaneously, partially, or full)
Just a thought…
Thanks 
thats what i want to do…back up the external hard drive that is already backing up the computer…u need to do this in case your first external hardrive backup fails…some folks have 4 harddrives continually backing each other up so that it is virtually impossible to lose your data…if u find out how to do this…let me know…i call my computer doctor now and ask him…u would think WD would offer this idea…as failure of external harddrives especially are frequent.