103: How to use the AFB?

[cereal killer]

I think I read that the 103 in Zusi has an AFB, am I wrong?.
I tried to activate it as I normally do in other locomotives, but I can't use it.
Can someone please explain to me how to activate the AFB and how to set the speed in the 103 please?
I then noticed that by rotating the traction regulator control to the end of its travel, a lever located on the right side of the regulator wheel is also activated.
What is it about?
Thank you.

[F. Schn.]

103 has three modes as indicated in the switch in the bottom right corner of the wheel:
Primary manual mode (mouse wheel up / Num 8/2/5 above zero) => set speed with wheel
Reserve manual mode (mouse whell / Num 8/2 below zero: Increase powe (lowest switch state) or decrease power (uppest switch state)
AFB mode: Activate with "A" when wheel is in zero; then set speed by wheel (Num 8/2/5) (No separeate AFB lever with 7/4/1)

[cereal killer]

Thank you again!