just to make sure: you are using an iphone 4S? and you have the office menu in the iDrive screen?
to read the messages you need to go to office>messages menu, where you can filter for all or e-mail, text or service messages. (if you can see the filter for email and text, but no messages, then make sure you have the right settings in iphone's notification center and wait for a new message. If you don't see email and text on the filter make sure you have turned on "show notifications" in iphone's bluetooth settings) Again only new unread messages show up simultaneously as you get the notification on the phone, not old ones.
If you are not in office menu, little message icon shows up on the right top of the screen indicating a new message.
F12 650i XDrive, Carbon Black/Cinnamon, M Sport 373M, Full LED, ARS, Active Cruise, Cold Weather, Driver Assistance, Premium Sound, Apps