Nokia Navigation :: Setting Created That Allows To Select Audio Output Via Bluetooth?

When my Lumia is connected to the car via bluetooth, its connected with both audio profiles, Voice (Phone Call Audio) and Music (A2DP).So when connected and Nokia Drive is running the audio is sent to A2DP to then be sent to the aux input of the car stereo. This is all well and good if you have the radio on and AUX selected. But if you are listening to FM radio or a CD etc you don't hear any voice guidance from Nokia Maps.

This is a question directed at Nokia Maps Developers. Can a setting be created that allows you to select audio output via bluetooth? If you could select it to go via the Voice/Phone call Profile, like for instance the Speech input works on Windows Phone, for reading/replying to text messages, then when ever there is a direction to be spoken, the car bluetooth would treat it as a phone call, cut sound to the radio and speak the direction through the speakers no matter what the radio was outputting.If the above doesn't make sense then please ask me as this would be a worth while setting to be developed.