Nokia 6021 auto on/off in my car... without a carkit. Possible?

I have a new car with full bluetooth support and my old and trusty 6021
works great, just lying on the passenger seat. So,. I don't need a carkit.
This phone supports ignition detection whereby when inserted in a compatible
carkit, the phone will switch on/off when the car is started/stopped.

In my situation I need to turn the phone on and off by hand. Which is a bit
cumbersome since a have a dual SIM and when I forget to turn the 6021 off,
my calls are sometimes not send to my other phone (Samsung Galaxy S) that I
use outside the car.

Is there some way to enable this on/off function without a car kit? I
understand that Nokia uses some sort of special serial protocol on pin 3
(Accessory Control Interface) of the pop-port to detect Nokia accesories
such as a Nokia carkit. Some command on this pin will turn the phone on/off.
Therefor I am looking for some external device that connects to this port
and sends this command when the 12V turns on/off.

In the accesory settings menu of the phone there is a setting within the
headset profile for iginition detection but this doesn't work although the
BT headset profile is used when communicating with the car. I can understand
this because otherwise the phone would switch off when a BT headset is
switched off, which clearly is not the way it should be. Somehow this
parameter will only be used by the phone when inserted in a carkit using
this headset profile.

Perhaps getting an old Nokia carkit and using the electronics from that
would work but most of these carkits come with Bluetooth also which I don't
need. And the very old Nokia carkits have this ghastly large box of
electronics and lots of cables, speakers etc. which I don't need at all.

Small chance I gues someone here has an answer to this but it is worth a
try....

TIA

Ernst