Now has generic action (no arguments though)

OpenRA.Game/Traits/HasUnitOnBuild.cs

@@ -28,7 +28,21 @@ namespace OpenRA.Traits
 						+ info.SpawnOffset, self.Owner);
 					var unitTrait = unit.traits.Get<Unit>();
 					unitTrait.Facing = info.Facing;
-					//unit.QueueActivity( new Harvest() );
+				
+					if (info.InitialActivity != null)
+					{
+						foreach (var mod in Game.ModAssemblies)
+						{
+							var fullTypeName = mod.Second + "." + info.InitialActivity;
+							var activity = (IActivity)mod.First.CreateInstance(fullTypeName);
+							if (activity == null) continue;
+
+							unit.QueueActivity( activity );
+							return;
+						}
+		
+						throw new InvalidOperationException("Cannot locate Activity: `{0}`".F(info.InitialActivity));
+					}
 				});
 		}
 	}