Alaska Resurface [WDTV LIVE HUB & SMP]

I have a small issue and maybe you can help me with that

I have 4 external Harddrives connected to the WDTV (working with a belkin-hub): 2 Movie HDs, 1 for TV-Series and 1 for Music.
Is it possible to give each HD a certain thumbnail which is displayed e.g. in the Video-Menu? I tried to put a “folder,jpg” in the root, but this won’t work.

[Edit: Former 2nd question solved meanwhile]

Thanx in advance