See the sticky thread on the wheels forum, the Touring 08+ uses a different sensor than other models of that year and of prior years.
IF light stays on, stability control system also enters a different mode as van believes the spare could be installed and thus cause rotational differences between wheels, etc. Research here, it's not just the light that you'll face.
Order TPMS from magauto.com or some other vendor at discount, they can be installed by a good shop without having to remove the tires but just by popping the bead by the valve.