This issues sounds strikingly familiar to some other issues where people have been having trouble adding their Gmail to the Microsoft account but I want to actually use my gmail address AS the login. For example I want to be able to go to any microsoft website or service and use "(username)@gmail.com" rather than "(username)@hotmail.com".
Problem is that when I go to create a Microsoft account is says that it's already in use but I don't recall creating so when I go to reset my password it says that it's not a Microsoft account". WTF?!?