Parrot ck3100

I've got a Parrot CK3100 hands free kit installed into my Disco.

The problem I've got is when a call comes through the volume comes out at full volume I've tried turning the sound down on the stereo,Phone and on the parrot itself but nothing is working.

Has anyone had the same problem and got it sorted ?
Because I haven't a clue when it comes to these things.

If you are using the stereo speakers and going in from the back of the radio it wont work as the "outputs" from the radio are line level going into the Amplifier rather than speaker level