Unable to set either of my Microsoft accounts as Alias’s for the other :o(

Recently I have installed windows 8 and setup and NEW Live ID I have gone through the process of transferring my Gamertag from the old to the new and I want to merge (alias) the old with the new. Frustratingly I am unable to alias my current outlook.com acount with my hotmail.com and vice versa. I spoke to the Microsoft support via the chat and they are also confused why at least one wont work.