windows 7 - How do you add an item to the context menu of a folder?

I know how to add a context menu for when you click on an actual folder:

[HKEY_CLASSES_ROOT\Directory\shell\commandNameHere]

but what about clicking on nothing in a folder?

like I make a new folder on my desktop, double click to enter the folder, then right click on nothing (the folder is empty), now I want my context menu to appear in this situation.