No Voice Guidance under Bluetooth

Question

The "No Voice Guidance under Bluetooth" problem seems to be well documented on this board as well as elsewhere on the web, and can be sumarize like this:
In-Car bluetooth connections that work fine for phonecalls will not relay voice directions from Maps, and the phone itself stays mute. In effect, no voice directions are heard at all.
The reason seems clear as well: The bluetooth standard allows for several different kinds of sound-streams for priority purposes etc. Most In-Car bluetooth devices however (including several NOKIA-ones), accept only actual phonecalls. Hence, all oher sound is muted while connected to the car.
The rather obvious solution would be to have a setup-item in Ovi-Maps that forces all sound from the program to use the phones integrated speakers instead of an operative Bluetooth connection. (Use Bluetooth connection for Voice directions On/Off). 
However, over all the posts, NO NOKIA STAFF have responded to aknowledge the problem or comment on it's possible solution or workaround. (And I have not found any third party app that adresses the issue.)
One might speculate that the reason would be the design of the operating system, choosing to handle all sound in a similar way, which undoubtedly is a good thing ... in most cases, but in this case dissalows usage of the free navigation in the one situation it is of the highest value - IN THE CAR.  
NOW - as FREE NAVIGATION becomes a major selling point and the aplication can't work in a modern car while maintaining legal phone connectivity, NOKIA needs to accept this reality, and make Ovi-maps useable for these users as well - even if that means defying a design principle. An actual response from someone informed, would be greatly appreciated.
For reference, I use version 3.03 10wk01 b05 of Ovi-maps on my NOKIA N97 mini with a factory fitted Alfa Romeo "Blue&Me" bluetooth kit, developed by Microsoft Automotive.

Answer 1

I don't have this issue. But then I don't have a BT system built-in to the car.
What I do have is a Sony BT Radio / CD / AUX which I fitted myself.
The Sony has 2 "channels" for BT input - "Music" and "Phone". I can connect my N97 using both of these channels,or only one. The SatNav function on the phone uses the Music channel, and the phone uses the Phone channel.
I also have an Archos 5 IT, which has GPS and BT. So I can connect my Archos for the Satnav, and the N97 for the phone, and the radio controls which output is muted, at the touch of one button.
I mention this to show that the Nokia N97 has all the technology and flexibility to perform all these functions perfectly, co-operating fully with other devices.
Can you say the same for the devices fitted in your cars? How long ago were these devices fitted? How long ago did you buy these cars? When was the firmware last updated? What standards did the in-car devices conform to in the first place.
Just a thought.