If you want to use Windows to control your RAID array you will need to format both drives and break the hardware mirror. Doing this will allow Windows to detect this as 2 hard disks. From here you can go into disk management, convert the drives to dynamic

I am trying to set up two new identical hard drives as a Mirrored array in Windows 7 and must be overlooking the funtionality in one of the drop down menus/right clicks in Windows 7 Home Premium.

In Windows they don’t call their RAID options by the traditional 0, 1, 5, 10 etc. Instead they use spanned, striped, and mirrored as the options for creating software RAIDs. Note: RAID-5, although one of the options, isn’t actually available in Window