Help bmw bluetooth issues

[devswap]

I have a BMW with a bluetooth hands free system. It has paired with the phone and works perfectly for calls through the cars system but the phone doesnt seem to be able to put media audio through the bluetooths system. This would be handy for satnav apps and music etc. I presume its due to an incompatibility between the BMW's system and the S4's - has anyone found a way around this or can suggest anything. I used to have a belkin bluetooth audio jack converter in my old car which I could use and then use tasker to switch to the cars bluetooth should a call be received but this sounds like a bodge it work around rather than a correct one.