I installed my Beta version of fusion, just to compare it with Parallels. At my surprise, they have full Vista Bootcamp partition support. I installed it, run it, it display as my VM options "bootcamp partition", i choose that, hit Start... and voilà ! So let's go Parallels, if VMWare guy did it, you can too !
You may want to go read the post on the VMWare forum from their Senior Product Manager saying to NOT use it with Vista. He clearly states Vista is NOT supported. And that there are KNOWN issues where using it with Vista will corrupt your partition. So if that is your definition of "working", then congratulations. I'm very suprised that given they are aware of the issues they didn't take the extra step of preventing people from installing. Since many people like yourself are unlikely to ever see this post on their forum.
That is not a supported configuration in Fusion and to run it on your system puts your partitions at risk. This has nothing to do with Parallels and the discussion should take place on the Fusion forum.