Managing personal Outlook.com account settings, security, and privacy
Dale,
I received the exact same initial response ... the person responding is working from a script.
I recommend that you reply to the email you received. Explain that their initial response did not address the problem. Explain the problem (auto-complete does not work when you type the first few characters of your ID into the new Microsoft Account sign in page). Verify, and then explain, that auto-complete does work on other sites you sign on to (such as netflix, gmail, facebook, or whatever other sites you logon to).
The above worked for me ... so you may want to give it a try.