UE 5.6 Setting cloud density of the VolumetricCloud System

Thx for the Answer Kemichar. You have been totally right. It was the wrong parameter i tried to set.
I now created an dynamic instance material with the setup, but still i get no changes in the clouds density …
Do you have any idea what I am doing wrong ?

Setting up the dynamic material instance:

Changing the value:

kind regards
stucki