Question: The issue is simple really. Instead of creating folders in Visual Studio, I create a directory structure for my project on the file system. How do I include all the folders and files in a project, keeping the structure?

If I "Add Existing File" on a folder named Services and navigate to a file in the directory structure .. Services > AccountManagement > CreateAccount.cs, it appears in Visual Studio like so: Services > CreateAccount.cs. I do not want this.

I have an entire directory structure worked out already, as I am mimicking our client developers using the same structure for organization. How do I add all the folders and files to the project in Visual Studio? Or do I have to do what most Microsoft users do and "put up with it" and recreate each and every folder through Visual Studio?

Answer: 
In Visual Studio 2013, I couldn't get "Include in Project" to work when right-clicking on a folder. What did work is expanding the folder, selecting all the files then choosing "Include in Project". It was quite tedious as you have to do each folder one by one (but at least you can do all files in each folder in one go), and it appears to store the file path (you can see this by viewing properties on the file and looking at the "Relative Path" option.)

I am hoping to use this to deploy some data files in a Visual Studio Installer project, and it seems to pick up the included files and preserve their paths.
I found no answer to my satisfaction, so I figured out myself.

Here is the answer to you if you want to add external source codes to your project and don't want to copy over the entire codes. I have many dependencies on other gits and they are updated hourly if not minutely. I can't do copy every hour to sync up. Here is what you need to do.

Assume this is structure:

/root/projA/src

/root/projA/includes

/root/projB/src

/root/projB/includes

/root/yourProj/src

/root/yourProj/includes

1. Start your VS solution.
2. Right-click the project name right below the Solution.
3. Then click the "Add", "New Filter", put the name "projA" for projA.
4. Right-click on the "projA", click "Add", "New Filter", enter name "src"
5. Right-click on the "projA", click "Add", "New Filter", enter name "includes"
6. Right-click "projA"/"src", click "Add", "Existing Item", then browse to the /root/projA/src to add all source codes or one by one for the ones you want.
7. Do same for "projA"/"includes"
8. Do same for projB.
Now the external/existing projects outside yours are present in your solution/project. The VS will compile them together.
Here is an trick. Since the projA and projB are virtual folders under your project, the compiler may not find the projA/includes.
9. If it doesn't find the projA/includes, then right click the project, select the "Properties".
10. Navigate to "C/C++". Edit "Additional Include Directories", add your projA/include as such "../projA/includes", relative path.

One caveat, if there are duplicated include/header files, the "exclude from project" on the "Header file" doesn't really work. It's a bug in VS.