W211 cassette deck "hack" as AUX input
 

My ride is an '03 E320 without the aux jack in the glovebox...Does anyone know of a resource/guide to "hack" into the cassette deck to install an auxiliary jack for plugging into iPhone/Droid? I've got a good one for a W210 system and wonder if the systems are similar before I tear into it. That one basically solders the wires of the jack into the R & L channels audio out, and operates by putting a blank cassette into the player. A much more elegant solution than what I'm currently using: a cassette adapter.

Thanks!