How is the RAID set up? RAID 0? RAID5? RAID10?
Usually if it’s RAID 5 or 10, it takes a different utility than the basic Apple Drive Utility to format the drives correctly for redundancy. Did you check with the manufacturer on their procedure to format the RAID? I have several RAID5 G-SPEEDes units and I format them with the G-Tech supplied drive utility software to create a RAID5 array and not the normal Drive Utility provided by Apple.
Just a thought.
E=MC2+/-2db