Send event from guidance to fsup


I would like create a landing guidance and I don’t know what is the right way to do it.
The use case is to land move drone above a specific image (tag) and change mode to land (landing.normal). So I created a mission with a guidance command and a new guidance mode to move drone above the tag.
Now how I can send event from guidance to fsup to say the target is reached ?

I see this topic Stop rotation when exiting mode - #2 by Ronan but there is no exemple to made this neither example in documentation.