RAID 5 requires a minimum of 3 drives.  You could do software RAID5 with
partitions, but that would be pointless.  With only two drives you can do either
RAID 0 (striping) or RAID 1 (mirroring).

> it may not be supported hardware wise,
> but you may be able to use the raid routines in linux and go raid-5 by setting up the partitions in linux.
> 
> I'm am not sure how to do this myself, but I might experiment with the 2 4.3 gig drives I've got just to see if it works.