Vibrating and pulling to the left Sedona 2007

[CFP2656]

Hi,
I am new here. My Sedona is 2 months old. I am waiting for an answer from Kia but thought maybe someone out there has the same experience.

The Sedona is a beautiful vehicle, solid and smooth riding. Since the very first day however, this one tends to pull to the left side of the road, even if I drive accross the white line, except if the wind realy blows hard from the left. When the wind does blow hard it tends to follow the wind direction which make me wonder if these problems are not all to blame on the tyres.(?)
Besides this the rear of the vehicle, when unloaded with passengers, is vibrating causing continual noises - rattling and squeeking of the leather seats; like you would expect from a hard suspention on a light rear end. There is no detectable vibration in front or on the stearing wheel.

Kia agent had the vehicle on Monday and Thuesday this week for testing and has now sent a report to Kia Korea, (I presume). Wheel allignment and everything about that has been tested by experts twice. Tyres has been changed around and on the rim. Preasure has been reduced to 2 Bar instead of 2.6. Various road surfaces has been tried, even the most smooth imaginable. Who can help?