EzAPI - Creating a SSIS 2012 project

I'm trying to create a SSIS 2012 project using EzAPI. However I'm unable to open my project file in Visual Studio after I've saved it to disk.

The code im using to create a simple project containing one package is the following:

EzProject MyProject = new EzProject();
EzPackage MyPackage = new EzPackage();
MyPackage.Name = "MyPackage";

MyProject.AddPackage(MyPackage);

MyPackage.SaveToFile("C:/Temp/MyPackage.dtsx");
MyProject.SaveAs("C:/Temp/MyProject.dtproj");

As expected my C:/Temp folder contains the package and the .dtproj file. However I'm unable to open the dtproj file in Visual Studio. The error I reveive when I try is:  "Exception from HRESULT x80041FEB"

Also when I open the .dtproj file in notepad it does not contain XML like a .dtproj file should. It contains some gibberish with alot of special characters (for example: eQMs‚0¼wÆÿÀä$| )

What am I doing wrong?