Pioneer didn't make this an option. When the AppRadio is in 5 mode the iPod app is completely disabled. I just tried this myself.
It's infuriating for two reasons
1. The AppRadio actually fully supports this. Android phones are controlled exactly the same way as the 5, and AppRadio fully supports (it is actually one of the features) letting you run an Android phone and an iPod at the same time. However the iPhone 5 is locked out of this feature.
2. CarMediaPlayer sucks!!!! Oh my god the built in iPod app on the AppRadio 2 is so much more powerful! The only thing the CarMediaPlayer has going for it is app smoothness. The built in iPod app is more powerful by miles.
Things the iPod app does that CarMediaPlayer doesn't.
1. lets you go back to the previous page you were at after you've already picked your song. Fantastic for when you accidentally click the wrong song.
2. Lets you jump to right where the song is in your library from the song page. This includes being able to see where the artist is in the artists page, where the album is in the albums page, and where the song itself is in the song's page. THE BUILT IN IPHONE APP DOESN'T EVEN LET YOU DO THAT!!!!!
3. See track metadata when in other apps by double pressing the home button.
It's an amazing app and I so wish Pioneer will update the CarMediaPlayer app to give me some of this functionality with the carmedia player level of smoothness. I miss that iPod app so badly.