Twonky Scanning a USB attached hard drive?

I wondered if anyone can help…I have a 1TB MBWE white light but my video collection has out grown the 1TB.  I have attached an external hard drive via the USB socket and transferred all my movies onto this device.

However, I cannot seem to get Twonky to scan the external hard drive!

Is it possible for twonky to scan the drive and, if so, how would I get it to do this?

Many thanks in advance.

I am assuming that, by the lack of reply, it is not possible to get twonky to read USB attached drives?