mynameiseldin

Do they have it, i opened the door sill and i dont see anything thats white.

acr2001

No. Many features including all prewiring were made optional for 2007. Don't ask me why, I guess MB wanted to save some money and screw the 07 buyers. You do get an updated power-train!

You can pull your head unit and connect the aux input from there. Search for a very nice how to with photos.

W203E35

acr2001 is 100% correct. Some of the older build do have this on the 07 model. I know a member here who his car's build date was October 06 and he has it. It's a hit or miss.

I hope these instructions help you with removing the stereo.
Basically pop out the trim and you will have bolts. Remove bolts and that's all there is to it.

AdidasC230

You dont have it, but there is a MB OEM ipod integration kit (not just an aux in like you where hunting for) which charges while it plays, however is limited in its control through the menu, I herd its 300 for it and 200 for the instal. You may want to look into it, if you really want your ipod to be able to be plugged in.