Any update on this? I would love to be able to route music through the 3.5mm headphones, and have calls routed through bluetooth headset. Instead, everything seems to route to bluetooth even if 3.5mm is plugged in.
I regularly connect my phone to my car stereo over 3.5mm to listen to music, and my (stupid) state just passed a 'hands-free phone' law, so it's currently impossible to have my bluetooth headset on and ready in case I get a phone call AND listen to music through 3.5mm on my car stereo..

EDIT: I drive a convertible, so using a bluetooth car stereo for music + phone calls is not feasible, as there would be a lot of interference from wind on a dash-mounted microphone