Blend and Source control

It is all well and good Microsoft saying that a developers and designer can share the same project WPF/Silverlight files in Visual Studio and Expression Blend, but whilst Blend does not have the ability to use a source control repository (TFS, SVN or anything else for that matter) and actually strips out  any source control binding it finds in a project file, this is for me unworkable experience. How has this product got to V2 without this feature?

For any company interested in a quality development process source control must be the most basic safety net, irrespective of how agile their methodology is.

I suppose there is one agile model where it could almost work and that is the designer and developer pair programing on the same PC with Blend and VS installed - but how realistic is that? and certainly does not scale beyond two people.

So as I am at Remix, I just asked Scott Guthrie when we would see source control in Blend - he said next version, some time next year, but on the plus side it should also include TFS work item integration. All good but we need it now, this is such a barrier to adoption of the Blend products.