So you have 5 disks.
and windows see's all 5 disks.
that means that you have no hardware raid at all, (as in that case windows only see's 1 disk)
when you look at disk manager, (which I assume you already did to see that your disks are dynamic and not basic) that tells you what the disks are doing
look at the picture on the bottom of this page:
Raid 1 (Disk Mirroring), Implementing disk mirroring on a Windows server 2003
you see that the drive D: is on two volumes.
the column titled layout tells you what RAID level you have.