For the handful of us that drank the coolaide early and missed out on the STFA there is a TSB out to add it now. TSB#08-021-20RevA. Had mine done last week and works as promised in the owners manual. Hope that helps.
It actually works better than in the manual. It says you can only air down/up one tire at a time. Not true. I do all four at once, both ways, and it still works.
From how the TSB reads to me if you were supposed to have it you can have it programmed in. I'm not sure what all models came with the option. The sales code is LA5. I don't know if it can just be added to any vehicle though.