Leaving for home now....if I can remember I'll throw a tape measure on it and get back to you tonight.....
by the way....your english was nearly perfect on this post!!
edit...here is a pic of mine that just shows the edge of the platform, it looks to be about 4-5" below (100-125cm for the rest of the world) below the cut out of the transom.....will get you a better dimension hopefully tonight.