JT.S550

Hey people, I wanted to know if you can possibly help me out, my friend gave me his iPod integration kit from a 2007 s550 and I installed it in my 2007 s550. I never had an iPod kit and I'm told my car is early 2007 where they didn't come with it and in later 2007 and on they installed them. My problem is in my command I don't have the AUX option in my AUDIO, I'm told it has to be activated with the star, I been to Mercedes dealer and on phone with a few others and they are clueless, they think I'm the crazy one. Could anyone possibly show me how to do this with STAR, I really would appreciate any information, possibly a step by step on STAR, thanksss