With the new organization, if you want to change directly, you have to know which driver is used, which makes this module not generic enough. By going through commands, it is the command_laws that takes care of using the correct servo (I'm still need to merge FW and Rotorcraft commands...).
If you prefer, I can directly set the actuator by using the actuator array, but in this case, the command_laws must not be used, and I need to set all actuators even if their is no command_law associated.