Create in Category Class Methode searchByPath:
public static function searchByPath($id_lang, $path,$objectToCreate = null, $MethodetoCreate = null)
use for search an category by path : "/cat/subcatg0/subcatg1"

Edit in AdminImportController :
Possibility to import category and subcategory for product
describe by "/cat/subcatg0/subcatg1", if not existe,
can be create recurssively.