It did work. It was beta 2 that put a kibosh on that. McAfee and Microsoft are both working on it. I am sure they will get it fixed by the final release, which isn't going to be for a while yet according to my sources, it's in both their interests to do so after all.
Beta 2 has deleterious effects on several applications from what I've read.
I uninstalled IE8 on all mine (XP Pro x 2, Vista Ultimate) except for my Windows 7 pre-beta which has its own unique version of IE8. I can't vouch for McAfee on that as I haven't been able to install it so am using other applications.
I found IE8 is most definitely a "work in progress" and had to resort to Firefox as my default browser anyway, so I didn't see much point in using it.