What happens exactly when I plug a USB storage into My Book World Edition II USB port

I haven’t tried this before because I want to understand it first. If I plug some My Book Passport lets says into the USB port of My Book World Edition II, will that create a new drive that I am able to see through the network share, or will simply only transparently increase the storage??

I would be very interested if you get this answer!  I have been trying to connect a MyBook Essential onto my MyBookWorld (network) and I can’t seem to see it at all.  I think it has something to do with the lock (password).  I tried updating the firmware and software to disable VCD (?) and I guess not apply the password…but when I plug it into the back for the MBW, it still shows the lock as lit.  So, I don’t know what to try next.  

even i m in want for an answer for this question!! my world book is full with files and i want to extend it with an another 

1 tb of I omega HDD… when i connect it  to the rear usb port of the wd drive nothing happens?? i donno why??

Has it been formatted in compatible format with the My Book World drive?  You should be able to go into the My Book World’s UI and format it from there.