The answer as I understand it is this: A personal domain name is not a supported option for O365 Home Premium. If you want to leverage your own domain, you will need to sign up for O365 Small Business.
This is my understanding. By comparison to Google Apps, I believe they support it but I think you need to be paying $50 per user, so depending on your user counts...O365 Small business is the same cost per user.
Personally, I'm grandfathered in on Google Apps with the free setup for 10 users or less. I would not be able to sign up for it today but I'm supported for now with my 6 users on my personal domain for free.
I'd like to switch to O365 as I don't get much use out of the Google Apps and would prefer MS Office and OneNote integration, but can't justify paying 6x$50.
Good luck. I would like to be corrected if O365 Home is different than I understand. Clark