GM steering wheel controls interface

i will be working on an 99 olds aurora that has radio controls on the steering wheel. there is im sure, an "information" lead that runs to the factory system that would relay the info from the steering wheel to the factory radio. we will be removing the factory radio and installing a pioneer premier head  unit and i want to install one of those peripheral devices that will interface the factory steering wheel controls to the aftermarket head unit. i was told there was an "information" wire in the factory harness. has anyone worked on one of these?

thanks Sparkie!