I think there are 3 things that have to be true to get the little guy to appear in your scenario's text.
1. You have to be using objective scoring, i.e. 1 or 3 points for objective cities.
2. Player 1 must be the protagonist.
3. When you save the scenario file, you must save it as player 1 with the unit you want displayed as the active unit.
If you are not using objective scoring, you can't do it.