I'm trying to play Spotify through the USB cord on my iPhone 5 in my 2012 jeep grand cherokee (RES 130 stereo with UConnect). When I plug it in it automatically starts playing music through the native iPhone music app. If i go to Spotify and press play it will play the song for 3-4 seconds then go back to the native music app. I've gotten it to play one song in full and then it will go back to iphone native music. I've gotten it to play 3 songs, sliding forward to the next song after playing for 10 seconds, and then it goes back to the native music app and wont go back. This has to have something to do with iOS 6 and spotify. I know it's worked before. Is there any way to override the native iPhone music app and play spotify? Is anyone else having luck playing spotify on their iphone through the USB of their car? Any help would be much appreciated!

Note: I can play Spotify with bluetooth turned off thru AUX, but that renders my bluetooth phone options useless. I can stream the audio through bluetooth but the audio is unbearably terrible.