We don't have a copy of Parallels, but will be testing in a VirtualBox environment soon. This isn't our highest priority, as I hope you can understand, because, like you said, this would affect a very minor amount of users.
We'll let you know what we find, as we investigate further, and certainly, let us know if you determine anything as well.
Thank you very much for the review. It just posted, and it helps a lot!
Facebook login failure in both IE7 and IE8
