CTE query doesn't print the right structure?

Question

I have this table which represents hierarchy :

childID  parentID          NAME          siblingOrder
1          1               a               0
212        1               ab              1
112        1               ac              2
412        1               ad              3
-912       112             aca             0

The structure is:

a
+----ab
+----ac
     +---aca
+----ad

(The siblingOrdercolumn is for controlling the order of ab,ac,ad )

I already have this solution which uses the siblingOrder :

;WITH CTE AS(
   SELECT childID, parentID, 0 AS depth, NAME , siblingOrder,
         CAST(RIGHT('00000' + CAST(siblingOrder AS VARCHAR(6)), 6)  AS VARCHAR(1024))  AS PATH
   FROM   @myTable
   WHERE   childID = parentID 
    UNION ALL
    SELECT  TBL.childID, TBL.parentID,
           CTE.depth + 1 , TBL.name ,TBL.siblingOrder,
           CAST(cte.Path + '.' + RIGHT('00000' + CAST(Tbl.siblingOrder AS VARCHAR(6)), 6)AS VARCHAR(1024) )
    FROM   @myTable AS TBL
            INNER JOIN CTE  ON  TBL.parentID = CTE.childID
    WHERE   TBL.childID<>TBL.parentID
)
SELECT path,depth, childID, parentID, siblingOrder, REPLICATE('----', depth) + name
FROM CTE
  ORDER BY PATH

So order by PATH actually do the job :

The problem:

The problem is that I Must(!) put values in the siblingOrder in order for it to work !

Otherwise , For example :

If I put 0 in all siblingOrder this is the result :

(yes, now sorting by path - doesn't work...)

I need that aca will always be under ac

(The only reason I added the siblingOrder is to order siblings !) and I don't want to enforce adding siblingOrder when not needed

Question :

Is it possible to enhance the query so that siblingOrder will affect only to siblings ?

I mean , If I don't care about the order of the siblings ( by putting 0) , I still expect the aca to be under ac

Sqlonline : with siblingOrder

Sqlonline - without siblingOrder