I wrote earlier about how ASP.NET Routing does not really work with Web Part Zones. Both are interesting and useful features on their own, but they do not work nice together. You can read more about it here:
.NET routing and Web Part Zones == an impossible mix
I had Visual Studio 2010 Beta 2 and the .NET Framework 4 Beta 2 installed recently, so I thought I would give it a try and see if this bug has been fixed.
Unfortunately it seems that the developers at Microsoft have been working on other interesting features, because the example that I presented before does not work in VS2010. Of course this is only a beta release, but if this hasn't been fixed to this point, I think it will remain unfixed.