Hello bnwgraaf,
on my F930BT in combination with an Iphone5 it works with the app "BT mono", which is available for android, too (https://play.google.com/store/apps/details?id=com.bedoig.BTmono&hl=de). It roots the "spoken text" from A2DP-protocol to "hands free"-protocol internally. So every bt-audiostream is handled as an incoming call, as I have understood...
Tests with two other BT car radios have shown full functionality, but the switching time for example in a Ford audio system is rather long...
With our Pioneers even short messages are to hear nearly in realtime
I use BTmono