On my car, it's two small cylinders close to the battery... the engine in your car should be the same as mine (2.8l M104) so it might be in the same place. I took a photo of mine, but the cellphone camera turned it into a black and grey streak, so it's useless.
Phil has this for sale for your vehicle - R3035-85752 - but mine looks a little different (one of the cylinders is taller then the other):
