Is this it? I don't know anything about this device, so it might be unrelated.
ata1: PATA max UDMA/100 cmd 0x1f0 ctl 0x3f6 bmdma 0xd000 irq 14
ata2: PATA max UDMA/100 cmd 0x170 ctl 0x376 bmdma 0xd008 irq 15
I had to fight our thin clients (WYSE S30,S50,9150SE) to get access to their local storage. Hopefully this will be simpler than what I had to go through them working.
Can you test using another distro or installation disc (such as the Gentoo 'installer' or Parted Magic) just see if it shows up? If it does, the dmesg should help.