Edit drivers/engineers faces

[Popov76]

Hi!

I am currently playing with the F1 Manager 2021 mod, and I edited some engineers with the MM Save Editor.
I don't like the actual template that is used for the unofficial drivers (it's just a black helmet with the mod) and I want to add faces by myself with real images.
I searched for a long time but found nothing, how can I edit these faces?

Thanks in advance!