The mounting bracket to absorb the torque it's fixed on an original mounting point of the servomotor:
The ECU is completely invisible under the dashboard:
I am really looking forward to receiving the U-joint because it is the only element that could still cause me a problem.
I should receive the ServTronic control module tomorrow. I will be able to make the electrical connections and do a first test by creating a resistive torque at the output of the servomotor with a clamp.