That's because the audio head units for Mercedes models are different from line to line, and for whatever reason (most likely engineering constraints, marketing decisions) they haven't been able to roll out the iPod integration across the line. Basic...
probably not but regardless you can go to any major electronics store and get a cable that plugs into the i pod and has video and audio output.(red white and yellow rcas) then you can plug it into the a/v in on the back of the headunit.
The Camrys with the base audio system have a single (standard in the CE, LE, and SE). The premium JBL system has a 6 CD changer in the dash, except for the hybrid with the Nav system, which has a 4 CD changer in the dash. I was told it was due to the...