Have you checked the adaptec website?
I had the same fear with my card, but mine was a Advansys one. Because I had 2 different model numbers printed on the card I was unsure of what it was.
Mine said Advansys ABP-930/ ABP-940U on it. Please note the U stands for Ultra SCSI, which the new Plextor drive needs. I disabled the option for Ultra SCsi on my card, but the drive was still picked up. However when i burned at 8x and 12x the writing use to stop. So I needed the Ultra scsi option on!
Anyway, by the writer and if it dont work, buy and new SCSI card. they only cost £30 for an Advansys one!