如何通过webtest接受文件下载？

I'm using Visual Studio Team Foundation Server 2008 Team Suite to create a webtest for a site. On some pages the response is a file download (usually a PDF), and I just need to test that the response comes back with the right status code and content type, ignoring the body. When I run the webtest in Visual Studio, or run the compiled test with MSTest and load the results, those requests fail, causing the entire webtest to fail.I'm using Visual Studio Team Foundation Server