I have an installation project that needs to add 1 simple string to the registry, and the built in Registry Editor in the Setup Project doesn't seem to work at all. It puts a base key HKEY_LOCAL_MACHINE\Software\[Manufacturer] by default into the install project, and that doesn't even work.
Here are the steps I used to add the key.
EDIT: Take a look at figure 5 on this webpage. It shows you kinda of what I see except in what looks like a much older version of visual studio.
I don't see how this could fail, it should be so simple. I've even tried simple keys and it just won't create anything, or at least throw an error. I've seen this solution but its ridiculous to add a post build step to manually edit the registry when there is built in functionality to do it. That post indicates that the feature is just broken, so don't use it.
If you have a 32-bit installer the keys will be redirected under HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\ key
More details you can find here: http://msdn.microsoft.com/en-us/library/windows/desktop/aa384232(v=vs.85).aspx