While I am on hotmail.com I have set up the "sending email from other account" such that the receiver can see the sender as email@example.com instead of firstname.lastname@example.org. However the Surface RT mail app does not support this.
The trick to enable the ability to use an Alias is to use your Hotmail or Outlook.com online account the same way you'd use the Mail app. From the IE10 UI go to your Hotmail or Outlook.com account (you'll want to use this as the Microsoft account you use to login to the Surface). In IE10 UI you will want to pin that webpage to the Start screen (the Tile will say Hotmail for Hotmail accounts and Outlook for Outlook.com accounts), If you also save it to Favorites you can then drag it out of IE10 Favorites in the Desktop which creates a shortcut to it there (the Shortcut will say Hotmail or Outlook and your email user name).
To be on the safe side be sure to add the Outlook.com account to the Mail app, so you are extra sure all the Microsoft apps will sync up. The access to the People, Messaging, Calendar and SkyDrive apps are far easier within the Outlook Tile than the Mail app. If you are using the Hotmail or Outlook.com Tile exclusively for email, the Mail app can be unpinned from the Start screen (you can always add it back to the Start screen later, if desired).
The trick to IMAP is the outgoing server (which is SMTP) has to have SSL security checked (so your provider needs to offer SSL) It does not work with unsecured mail on the outgoing server. I went round and round with MS on this when I first got my surface. Still want POP3 too since my personal email account doesn not have an IMAP option.
It is a bug they are working on. They have had me send files to them from my Surface but I gave up on them and just started using SSL and then workarounds on my other email accounts. I am more frustrated at the lack of POP3 support.