wait until VS.NET 2005, :-)
here is a comment from Microsoft
As Steve has mentioned, the problem that VS.NET will auto-formatting the html source when switching between design-view and html-view is a known issue of the VS.NET's current version and which hasn't been fixed now. But this issue is to be fixed in the next version of the VS.NET (Whidbey):
#Preview of Web Development with Visual Studio Whidbey-----Better Source
Also, since this issue still remain in the current versions, I apologize for any inconvenience it brings you.
Microsoft Online Support