If the game ends with a numbered trigger End#1, End#2, etc. then you automatically get the Win Outro after the debriefing.
If the game ends with a Loose trigger then you automatically get the Loose Outro.
I haven't tried it, but I don't see why you shouldn't use variables to control what is shown in each outro. For example, if you had two "win" endings you could create two different camera scripts. The one to be played would be determined by variables, set when the mission ended.
For example, in the game you have two triggers:
Type: End#1
On Activation: end1=true; end2=false
Type: End#2
On Activation: end1=false; end2=true
In the Win Outro, also two triggers
Condition: end1
Activation: [] exec "camera1.sqs"
Condition: end2
Activation [] exec "camera2.sqs"
Of course it's better to start your camera script from the init field of a unit than a trigger, but you get my point. The camera scripts can include appropriate deleteVehicle, setPos an dother commands to make sure the end1 outro doesn't have end2 stuff in the background. Ideally the two outros would be set in different parts of the island so that avoiding conflicts is easy.
An alternative is not to use Outros at all and just have cutscenes at the end of the mission. I often find that more satisfying anyway.