1) create MP-mission and create a task using task module
2) create module "setTaskState" and link both
3) create a trigger to define when task is complete
4) link trigger with setTaskState-module
5) open MP-server (I did not use a dedicated) and let join somebody
6) in the briefing the joined user sees all tasks as completed right away, the server will see that over time the task(s) is(are) completed (before even starting the game).