I have one, a kenwood 9260BT, with the PAC it was all plug and play, have you tried re installing your OEM unit and see if that is giving sound, I asked you in a earlier thread if you had OnStar, I asked that because is you PAC not for the OnStar unit? I have a 07 SRX, yours is 05 so the PAC is different then mine. If you had a extra speaker laying around you could tap into the wires from the head unit to see if you get sound, for example tap into left speaker from head unit. Also your Head unit has support emails, for example I type in Kenwood Europe and it gives me the names of the closest kenwwod dealer/installer and a tech support, I am sure yours does too, and there are install shops in France, if they can install pioneers and JVC they can install any head unit. you have the schematic for your radio, thats all they need or they have their own web based info for every car.
You mention " Pins of SRX plug and PAC plug are not opposite." they may mean you have the wrong PAC. You should not have to do any modifications it plug and play if you have the right PAC