Changes to VC# from Visual Studio 2010 to 2013

Good morning. We are attempting to upgrade our companies codebase to Visual Studio 2013, and are running into problems. Our work requires us to access and manipulate Visual Studio project files for our customers. The first, and probably primary error, is that there is no longer a FileType property under the Microsoft.VisualStudio.Project.VisualC.VCProjectEngine.VCFileShim type.

foreach (Microsoft.VisualStudio.Project.VisualC.VCProjectEngine.VCFileShim ProjectFile in (IVCCollection)Project.Files)
              {
                  if (ProjectFile.FileType == eFileType.eFileTypeFilters)
                  {
                      //Don't do anything with filter files.
                      //The Project.Save() method will update them, later on.
                      continue;
                  }

FileType does not exist in the context above. This code compiles in VisualStudio 2010, and on a computer with both installed, but not on a computer with just Visual Studio 2013 installed. Has this been changed, and if so how would we go about fixing it.

The other major problem is that 

using Microsoft.VisualStudio.Project.VisualC.VCProjectEngine;

is causing a compile error that "Project" does not exist in the namespace "Microsoft.VisualStudio". There is a dll with this same name in the VC13 Program Files folder, and it seems to recognize it before compiling, but not after.

Thanks.