using alias as primary email

So I have a Microsoft account that I have been using to login to windows since windows 8, in the format mailto:me@mydomain.com

The email for mydomain.com is NOT hosted with Microsoft, it is used only for login.

Then I decided to make use of Microsoft free email account, this was back when it was live.co.uk

so I added an alias of mailto:me@live.co.uk

This used to work with the old windows live mail.

Since it has become outlook.com, everything has changed and I now have a problems.

It wants to use my primary login as the email address, which of course it cannot since it is not hosted with Microsoft.

If I try to add mailto:me@live.co.uk to outlook desktop app, this doesn't work.
It creates a user named "outlook_DE4D13B44.....etc" and won't actually download the mail.

I cannot change my primary alias to mailto:me@live.co.uk as this will break all the services which I have linked to my Microsoft account for authentication.

Is there any way I can still have my Microsoft login as mailto:me@mydoamin.com but use mailto:me@live.vo.uk in outlook