Hi Théo!
EMU PRO has a very advanced paddle shift system with several stages.
Go to Drivetrain / Gearbox / Type and choose Sequential paddle-shift. Then go to Gear shift / Actuator outputs. There you can set the outputs for each solenoid.
You can find a short description of the stages in the help menu (press F1) in Drivetrain / Gearbox / Gear shift.
Also check Drivetrain / Gearbox / Gear shift / State. I recommend setting the logging frequency for this channel to 500 Hz.
Please also see this post with an example project and log: