[SOLVED] Portable HDD with Powered HUB

[zilexa]

Directly to the Pi (with Pi connected to hub): I hear the harddisk ticking softly, every second. As if its getting not enough juice.

I bought two the same hubs, so I replaced the adapter+hub for the new set: now the harddisk is clearly vibrating softly, as it normally does when connected to my laptop or Netgear mediaplayer. Unfortunately fdisk and lsusb show the same result.
dmesg