I think you can. Howver, before you proceed down the RAID route, do yourself a favour and visit some of the many threads here concerning installtion of Windows 7 and RAID arrays. Generally, it has been a very unhappy experience. Use the SEARCH fucntion on the forums to check them out.
I do not believe you will gain significant benefit out of installing the OS to the RAID. It depends exactly your reasons for wanting to use the RAID option in the first place. Don't forget that RAID0 has no redundancy : one disk fails, you need to rebuild everything.