Aux Input on radion?
 

I have a 2004 230 and am wondering if anyone has a solution for MP3 hook up. The cassette adapter does not work for this. It thinks it's is still open (even if it's closed) due to the cable coming out and continues to beep every 30 seconds (anyway to disable this?). This is not an iPod, but a different MP3 device. I've not had good luck with any of the FM tuners. One dealership told me they can't add an aux input. Any suggestions?