Towing a Mustang w/ Penske?

I am moving across country in 2 weeks from AZ to MI. I am renting a 16ft Penske moving truck and plan to tow my 2006 Mustang on a flat bed i am renting from penske (where all 4 wheels are off the ground) but i just read that 17" wheels and above are non tow able... I have 17" pirelli's on my car. Now they know what kind of car I'm towing, they even say it when i went to look at the moving trucks. And they never said i couldn't tow it. So whats the deal? Can i tow it or not, i leave in 2 weeks from today.....its rear wheel drive, so I'm not just putting two wheels up on a car dolly, i heard that will ruin my driveshaft