First off, it's "loose outro" not "lose".
But lets get back to the beginning.... The Intro will play automatically before the Briefing. Export your mission to SP missions and then play it from the Main Menu and you'll see what I mean.
Now, to make your mission end you need an end trigger
Activation box: East not present (or whatever)
Type: End#1
If you have more than one trigger of type End#1 then the mission will end only when ALL of these triggers have been fired. Similarly with End#2 etc. When the mission ends in this way, the Win Outro will be played automatically after the debriefing.
If you want a loose ending, then your ending trigger (which in your case will have the lose conditions to activate it) is
Activation: as you like
Type: Loose
The mission will end when ANY trigger of this type is fired. The loose Outro will play automatically after the debriefing.
Edit: bah, too slow again