And i think, Kaliyuga understood your question, but what
he's trying to tell you (between the lines) is, that the
condition of presence can't be used for that. (correct me,
if i'm interpreting you wrong Kaliyuga)
The condition of presence get's only hot, at the initialization
of the mission.
Conditions like: cadetmode, !cadetmode,
alive (name_of_groupleader) can be used in here.
To make units show up during the mission, you need:
createVehicle, createUnit (as Kaliyuga already suggested).
~S~ CD