play spotify in car (mercedes e-class)

[n0cud06]

Hi, I own a 2012 Mercedes E-Class. I'm able to stream music via bluetooth but the car music controls won't work. This is a big problem since I have to use the phone (somehow the stereo knows my iPhone is not playing from the default Music app. I don't have any songs downloaded there either). So my question is can spotify pretend to be the default Music or maybe can a third party app do that? I guess the second option is to sync my spotify music to the default Music app on the phone (or iTunes then sync) but I don't think spotify allows me to do that eithe :/. For whatever is worth - Apple's new cloud based Music app works great in my car.