How to add a file property in a visual studio add in?

Hey, I'm working on my first add-in and I want to add a custom property to the properties windows of any file or directory in the project.

So, if right now there are properties like "Build Action", "Copy to Output Directory", "Custom Tool", and "Custom Tool Namespace", I want to add another property, say, "MyAddinProperty".

After googling for hours I couldn't find any reference r开发者_如何学Pythonegarding this subject. Please help me out.

Using C# with Visual Studio 2010.