Can I setup a software RAID in Windows 7 using Virtual Hard Disks?

I convert my comment to an answer, as the comment by @C0D3M0NK3Y confirms it.

Windows will not accept dynamic virtual disks in a RAID, but the comment by @C0D3M0NK3Y confirms that fixed-size disks used to work in XP Professional. There is therefore an excellent chance that fixed-size virtual disks will still work with RAID in Windows 7.

It is actually quite logical that Windows cannot create a RAID over dynamic disks whose size is unknown and can change at any moment.

EDIT/ADD:

Had to try it to see either way for sure, and it works (when using fixed-sized VHDs):

Host OS: Windows 7 Ultimate, with two "Basic" disks.

VM OS: Vista Ultimate.

Created two "fixed sized" VHD's of 500MB each, one on each of the host's physical disks, and attached them to the VM (as the 2nd and 3rd drives).

Initialized the new disks in the VM and then converted them to "Dynamic" disks (in Vista's Disk Management).

Then joined them together into a RAID0 (stripe):

Worked like a charm, without any need to do anything 'weird'.