The answer is simple - he did break the speed of sound!
The speed of sound is dependant on temperature and air pressure.
At sea level, the speed of sound is 761 mp/h (1225km/h) assuming a temperature of 59 °F (15 °C).
At a typical cruising altitude of commercial jets (11,000m−20,000m) and assuming a temperature of −70 °F (−57 °C), the speed of sound is only 660mp/h (1062km/h) so at 729mp/h in that height range, he has broken the speed of sound.http://en.wikipedia.org/wiki/Speed_of_sound
And I thought it was going to be Bill Shatner doing the jump instead....http://www.youtube.com/watch?v=qAZrPMsTL1c