I can't seem to find or add "~/Library/Mail/V2" to the Search Scope. There doesn't seem to be such a place on my computer.
Also, when I drag and drop the user-defined file type "Search Email.alfredworkflow" into the window, it says "com.runningwithcrayons.alfred.wo... Alfred Workflow" instead of looking the same as your screenshot. (I'm very new to this and not particularly Mac-savvy) Regards,
Ryan