如何在iPhone设备上使用AVAudioSessionCategoryMultiRoute？

I would like to use AVAudioSessionCategoryMultiRoute, but unfortunately there is no example on apple dev center nor Google. How to use/implement AVAudioSessionCategoryMultiRoute in order to define 2 distinct routes on an iPhone ios7.0.4 ? My goal is to route audio both through speaker and headphones. (I know that is was not possible in the past, but I would like to try with ios7)I would like to use AVAudioSessionCategoryMulti