I want add property in editor with my customAIPath

I created CustomAIPath class inherited AIPath to move backward and check some path nodes when finding completed.

namespace Pathfinding
	public class CustomAIPath : AIPath
		public bool moveBackward;

but I can’t see property in editor because AIPath using custom editor.

so I try to add property when CustomAIPath added.

var isCustomAIPath = typeof(CustomAIPath).IsAssignableFrom(target.GetType());

but cannot find CustomAIPath in AIBaseEditor.cs

how can I add property?

CustomAIPath.cs file in default project
AIBaseEditor.cs file in AstarPathfindingProjectEditor project