You check the firmware by going to the Apple menu at the very top left corner and doing a "about this mac". Then click on "more info" and choose "Serial-ATA" along the left column and it should give you your firmware version for the OWC SSD.
I upgraded the firmware by creating a new "bootcamp" partition while in the existing Mac OS X installation by following the
directions here. Once I had Windows XP installed and running, I grabbed a copy of OWC's firmware update tool and applied the firmware upgrade. I then rebooted as instructed back into Mac OS X and discovered the issue was resolved. Satisfied that the fix worked, I reclaimed my "lost" capacity and removed the bootcamp partition (and Windows XP) and so far, no issues. Let me know if you need further help. Good Luck and Happy Holidays to you.