title: TFS2012 build server not restoring NuGet packages from in-house repository
body: <p>I've set up an in-house NuGet repository (a shared folder on one of our servers), and have added it to the "Available Sources" list in the Visual Studio NuGet settings on my PC. I'm able to successfully install a package into my solution from this repository.</p>
  
  <p>However on the TFS server the build is failing because it can't restore this particular package (message: "Unable to find version 'xxx' of package 'xxx'"). The solution is configured for "enable NuGet package restore", which works fine for packages installed via <code>nuget.org</code>. It's just not restoring the package from our internal repository.</p>
  
  <p>Permissions on the repository folder/share are fine. What am I missing?</p>
  
  <p>I'm guessing I have to configure Visual Studio's "available sources" on the TFS server too, but presumably these settings are user-specific? The build service runs as NETWORK SERVICE, so how can I configure NuGet for this user?</p>