@Christoph: sorry but i resampled it (so erased the old ones and replaced it). the new works. So the problem was the wav file for sure.
@Alexaudio : Maybe just use 4 layer and use the velocity modulator to control this 4 layer like it could have 9 layer. not sure it will be as good as real 9 layers. remember that old Roland MKS-20/RD 1000 piano had beetween 4 and 8 layers and a velocity layer to map the all 0 - 128 velocity steps. that was causing (in parts) his particular sound and velocity response for a 80's digital piano.
But maybe with your real piano it will sound as a "digital" piano. So not sure.... just an idea...