Exchange push, except for Gmail for some reason, has been a problem since 6.0 and has been reported to be fixed in 6.1 but no one really knows. I'm having a problem since Saturday where adding Hotmail or Outlook.com via exchange is being setup as a standard Hotmail account but only on iOS 6. It doesn't allow the 2nd screen where the remote server is entered (m.hotmail.com). Instead it goes to the final screen for selecting the services you want like mail, calendar, contacts, reminders. Then if you open the mail app and go to the Mailboxes screen, it shows the Hotmail icon and not the Exchange icon.