Microsoft has released a patch for Windows Vista Beta 2 that will make Symantec Antivirus 10.0.1.622 compatible. This is the first patch that I have heard of Microsoft releasing to fix compatibility problems.
In previous releases of Vista Microsoft has had some security updates but Beta 2 seems to have escaped any security issues for right now. It is nice to see Microsoft standing behind their product enough to ensure that compatibility issues are addressed. I am sure Symantec had to give them a little push to get the patch complete though.