If I (using a action) set the value of a unit variable to a building, how do I select that building in another trigger, for example if a use a specific unit event and try and use that unit variable alla that comes up are pre-placed units. I tried usuing 'a unit finishes training a unit' event but that only lets me slect the trained unit how do I manipulate the building if it is not preplaced and how do I manipulate only units that that building produces?