Smartphone satnav option

Using my Galaxy S5 with the tomtom Go app and have to say it's pretty good and easy to use. For some reason I can't listen to music on my Sena S10 headset and get the voice prompts from the app to 'cut in' when approaching turns etc. I know some folk on here use mobiles instead of dedicated satnavs. Does anyone have a fix for this ?
Thanks in advance.

Eventually someone answered the phone at TomTom UK ( nearly 20 minutes or music ) and the software does not include this feature. It will handle our mobile phone calls as you're riding along, just doesn't do music.
Call handler will pass this suggestion on as feedback for inclusion in future.

I'll just toggle the music on / off button in town where needed.

Minor inconvenience in truth.