Ford SYNC System iPhone Connected via Bluetooth But No Audio!? SOLVED!!!

I just purchased a 2012 F-150 supercrew with navigation and the Ford SYNC system. I have an iPhone 4 and had no problems connecting my iPhone 4 to the SYNC system via Bluetooth, but could NOT figure out how to get my music to play through the pickup's radio/audio system (wirelessly).

In hindsight the solution was so obvious, but yet it took me a couple of days to figure it out.! Posting this, hoping it saves someone else the same frustration - simply insure you change/touch the "Source (LINE IN)" screen button (option) to "Source (BTST)" - the other option is to push the 'voice command' (MEDIA) button on the steering wheel and give a "play Bluetooth audio" voice command (accomplishes the same thing);