Great ! Thanks Dino/Klifford, I`m searching the web for a while but did not have the idea yet to put this question into the TL forum.
Seems to be the product I was searching for...I searched a lot on youtube with "headcast".

I recently made some tries with gypsum* (for the negative & for the positive I filled it with a PU resin), but this seems to be the most professional way.
THANKS

* take care with your hair !!! Use at least on ton of vaseline on your remaining hair & eyebrows, otherwise you run into serious troubles...