They lied? Why, yes, yes they did.
The new elements presented to the Stewards several days after the 2009 Australian Grand Prix which led to the reconvened Stewards Meeting clearly show that:
a. Immediately after the race and before Lewis Hamilton attended the Stewards Meeting he gave an interview to the Media where he clearly stated that the Team had told him to let Trulli pass.
b. Furthermore, the radio exchanges between the driver and the Team contain two explicit orders from the Team to let the Toyota pass.
The Stewards, having learned about the radio exchanges and the Media interview, felt strongly that they had been misled by the driver and his Team Manager which led to Jarno Trulli being unfairly penalised and Lewis Hamilton gaining third place.