Hello Samath,
I have an HZJ-77 from Japan. The stylle of the rear doors appears to have very little change over the years. What I have is the bracket that attaches to the special hinges. There are two holes in the bracket that you can see in the pictures, where the support bracket touches the door. In those two attachment points I had to drill through the sheet metal to provide an extra support to the brackets. On the inside of the door I used flat washers and lock washers with some nylock nuts. I also used some hardware that I had to fill all the old holes that were from the original brackets in the door. I'll paint them white when I get so some extra paint. I did not reinforce the bracket with anything aside of some washers at this point. I may add a additional metal plating inside in the future with some epoxy to adhere it to the door.