Renault Laguna II, what signals goes from the remote stalk to the radio unit?

Hi.

I have a Renault Laugna 2 - 2002 model and now I have bought a multimedia car stereo (no brand) with universal steering wheel connector and I would very mutch like to use the original remote stalk in my renault to at least control the volume of my new radio, the setup menu in the new multimedia player looks like this, marked with red in the manual here USER MANUAL

The wires for connecting the universal steering wheel are like this, wires marked with red on the chematics here;
SCHEMATICS

Red - power output
White - wheel signal output
Black - ground


I have not yet tried to connect the original stalk directly because i am worried that i might destroy something;

Question;
What is the protocol for the signaling from the remote stalk for the radio on the Laguna2 (2002 model), what kind of signal is sent out from the remote stalk towards the radio unit?
Are there any possibilies to use my original stalk to control my new radio

I hope somone can give me an answer or direct me to someone who can help me.

Best Regards,
Jan