For people with iPhones trying to get the text message system to work, these are the steps are your phone:
1) Go to Settings
2) Go to Bluetooth
3) Under Devices choose LEXUS IS
4) Turn On Show Notifications
I like that it reads them to me, and it cracks me up that it reads "
" as "Smiley Happy", but the resuming audio thing is super annoying. Not to mention that if my phone ringer is on it plays both the Lexus message tone and my phone message sound -- which, by the way, is insanely loud if you keep your phone volume at full so you can maximize how you use the car audio.