I've recently got a GA-7VRXP, and I have plugged a cd-rom in one of the raid controller ports with no problem
You could, but it's not recomended, RAID controller is designed to work with ATA66 or greater while your CD-ROM is ATA33.
Usually what it does when you have CD-ROM in there is keep triying to access the CD-ROM like your CD led is always blinking eventhough you are not touching anything on your keyboard.