Voice active answering call problems when connected via aux

[Takeawaylobster]

Hi, I can voice activate making a call handsfree specifically when connected through aux via car stereo thus working as a great hands free tool. However if that person does not answer I am unable to hang up hands free. Also how do I answer call hands free. I can do this when not connected via aux through the "answer call" prompt, but will not work, or has the option to work when connected. Many thanks