Update: We've revised this post to clarify that this isn't exactly a new issue. The same problem existed in previous revisions, but the big issue now is that the separate thermal cable has been integrated into the SATA cable. It's similar to what was done before, just a little harder to get around now. But, you can get around it.
Update 2: Hardmac has a detailed analysis of the situation which we'd recommend you check out. It verifies OWC's findings, and recommends you short pins 2 and 7 to basically circumvent the issue. Why does Apple do this? The separate temperature monitor enables OS X to more regularly check the temperature of the system's drives without compromising overall bandwidth provided by SATA.
[Thanks to everyone who sent this in]