ReSharper 5 external sources in a .NET 4.0 project

I've read about the ReSharper external sources feature in ReSharper 5.

But when attempting to use it on a .NET 4.0 project, but my attempts to make it work / use it have failed.

Whenever I attempt to navigate to "Sources from Symbol Files" - I just get the message that the symbols are not available.

Are the debug symbols for .NET 4 开发者_开发知识库not released yet or are they placed somewhere else?

It works fine and downloads the proper symbols for .NET 3.5 projects.

Microsoft released sources for .NET 4 release, so R# have to work just fine. Some debugging information may be found in View -> Output -> ReSharper after unsuccessful navigation. Sometimes R# can't download sources or symbols files because of server errors on referencesource.microsoft.com side.

Check out How to see .net library source code with ReSharper 5 and visual studio 2010?