"Because the Windows 7 does not give you a chance to create a disk as dynamic during the install process - you will need to do this afterwards. As such - you will need to install Windows 7 on a single non-raid disc and the convert it to dynamic / add the extra drive after you have installed the OS. I suggest you perform the raid adjustments fairly early after installing Windows 7 to ensure you either get performance (Raid 0) or reliability (Raid 1)."
http://www.alanjlee.com/blog/a-few-n...software-raid/