Has nothing to do with the SSD, they are backward compatible (but Amy's have no trim control) with regular drives and work fine if you want to use them (for a task that is overkill). I suspect the fault lies in the Acard device. I'm not familiar with the one you have, only the 7720 SCSI to IDE. The info sheet on the ARS-2000SUP says it is an Ultra (?wide) SCSI Interface, that the firmware may need to be modified, and to check the compatibility list for supported SATA drives; under SSD's your OWC Mercury drive is not listed. Whew!
I just use a Acard 7720u/w with a $5 IDE to SATA interface and everything works. I get my Acards from Mech's site for ~ $100 and Mech can flash the correct firmware for you. Mech is an expert and either loves to help or does a fine job of pretending; give him 24-hours for an email response
As far as an SSD, I got one when NewEgg had a sale, plugged into everything, took speed ratings, decided it was better of in my Toshiba notebook and left it there.
Don't F--- with the parity, it is what helps define SCSI 1 from SCSI 2 (along with other good stuff like sync).
In summary, try emailing Mech (Mike) for his opinion, but if Acard says you drive is not compatible, you could take up the issue with them