So the audio doesn't work at all and people are hanging up on you.

Check the audio connections at the ULF and at the radio unit.
Check the mute (active low) and TELON (active high) are going into the radio unit.

I will try another phone to test your theory

I have tested a bit, the car is mecanically sound

I have installed now a rSAP (remote Sim Access Profile) and it did not work again.
after I disabled rSAP it worked!!!

I managed to make 2 calls - hope it will work after I reboot my phone

I still think it could be a range issue, seems strange that it can connect to the car but not make calls, (remember a call takes a lot more bandwidth) sometimes when my mobile is in my bag and I'm in the car and the phone rings it will cut out or break up the call, as soon as I take it out and put it by the armrest the reception is clear as day...

ok, but the BT antenna is in the boot...according to your theory I should have the phone placed closer to the rear of the car, right?

I would say it is worth a try, I didn't have to put my mobile in the boot... On, Inside or very close to the armrest where the pairing button and generic charger are located works great for me...

Thats the most I can suggest...

ok, it seeems that all I need to do is to add a new outgoing port in my BT menu on the phone

I have seen this option several times on my phone, but at the moment it shows only incoming port (com7)

anyone knows how to force adding this outgoing com port for Bluetooth on WM 6.5?

many thanks!

I think I am onto something here:

if the BT is switched on after I start the car, everything works perfect!

the only inconvinience now is switching BT on/off for each jorney (especially annoying during short trips with short stops - to the local shop, post office etc)

It could be your MS Mobile BT stack. Validate its functions with other BT devices.

I have an HTC phone with a "cooked" MS Mobile 6.X OS. I keep my BT on all of the time. I typically use one of three BT earphones, one of two stereo BT headsets and BT in two BMW's and the BT stack works fine with all.

I typically don't have any pairing problems with the X3 BT. Wondering why you are turning on and off your bluetooth?

My HTC BT settings are as follows:
I have BT turned on but not the checkbox for making the device visible to other devices. I am using radio firmware OS version 1.71.09.01

the only way I could get it work is to switch BT on straight after I turn the car on.
If the BT is on already before I turn the car on, the voice part of connection between car and phone does not work properly (the stereo mutes, but the sound from the phone is not coming through the car's speakers ;( )
phonebook and sms are transfered ok in any case.