Unit - Remove classification of A structure from GenericBuildingHere
Unit - Make GenericBuildingHere face 180.00 over 0.00 seconds
Unit - Add classification of A structure to GenericBuildingHere
Hope that helps. Haven't tested it, but from what other people say.. it should work.
vertical walls
Events
Unit - A unit Begins construction
Conditions
Actions
Unit - Remove classification of A structure from (Constructing structure)
Unit - Make (Constructing structure) face 180.00 over 0.00 seconds
Unit - Add classification of A structure to (Constructing structure)