said by RickNY:What you need to do is set up an Outlook.com/Hotmail account for logging in to your machine, and then on the web, add your POP account to the Outlook.com account. It's clunky - but if you want to use the native don't-call-it-Metro mail app, thats the only way it can be done. Be sure to set the "Send From" address to your Optonline added POP account.
Will this show the return address as ...@optonline.net?