I think he means those intel screens on the campaign where you have a small window showing a cutscene and next to it you have the selectable missions, primary or auxiliary..
Those are done with a dialog, and the only way to do that is to have a briefingless mission that only contains the cutscene stuff and the dialog, that's how I understood they are done in the campaign..
Those are the missions startring with S, like S02BeatenDog.Sara..