Invert Mouse Y axis

Greetings,

I've played SH3 in the past and that game had no way to invert the mouse, after a little digging I found which parameters to change in the Commands.cfg.
Now, 2 games later, that option is still aggravatingly missing, I just bought SH5 and had to go into Command.cfg to change the same parameters.
Problem is, it managed to invert the Y axis on the periscope, UZO, deck guns, etc, but moving about with the captain avatar inside the sub still has the default Y axis.
Anyone knows how I can fix this, cause at the moment I can't play the game, which is a damn shame.

Thanks in advance.