Hi John. Thank you for your reply.
So, basically, the engine fire handles allow the pilots to activate the fire extinguishing system individually in the engines or APU.
When pulled (from "bottom" 0: In to "top" 2: Out, I believe), they basically isolate the Engine/APU from all the systems that are connected to them in order to allow the insertion of the fire extinguishant element into them and optimize its extinguishing effect.
After pulling any of the handles, you can discharge the fire extinguishant from the LH Fire Extinguishing Bottle by rotating the handle to the left (3: Turned Left), or from the RH one by rotating it to the right (4: Turned right).
The handles are normally locked to prevent inadvertent activation and are automatically unlocked and illuminated when a fire is detected in the related engine/APU. However, there are some cases when pilots need to pull the Fire Handles and isolate the Engines/APU even when a fire is not detected. For those cases, there is a Fire Unlock Switch underneath each Fire Handle that unlocks them, which I was able to configure using the codes described in my first post.
#define EVT_FIRE_UNLOCK_SWITCH_ENGINE_1 (THIRD_PARTY_EVENT_ID_MIN + 976)
#define EVT_FIRE_UNLOCK_SWITCH_APU (THIRD_PARTY_EVENT_ID_MIN + 977)
#define EVT_FIRE_UNLOCK_SWITCH_ENGINE_2 (THIRD_PARTY_EVENT_ID_MIN + 978)
Obviously, I was pressing the respective Fire Unlock Switches when trying to configure and pull the Fire Handles without an active fire indication.
Maybe with this explanation, you will be able to work something out.
I am not a computer expert, but I read the FSUIPC User Manual and managed to understand most of it, and I will try to understand the Rotor Brake control method and Offset concept through the Advanced Manual.
Thanks a lot again!