It looks like there needs to be additional hardware to support two drives.

Addonics has an ide-scsi adapter for 1 drive - $85, and 2 drives - $105.

http://www.addonics.com/products/io/ad2idesc.asp

The single drive is about twice what I paid for the Acard.

Unfortunately - or fortunately depending on your point of view, the Addonics one is the LVD 160 SCSI - I have no idea if a regular 68 pin to 50 pin adapter would even work on those.