Actually hollow door not suitable for the screw in type.. if you use hanging on the top of the door type 10kg also no prob.

Oohh, hollow like that normal plywood bedroom door? Unless you change to solid, there is limit to how much weight it can handle.

How do you put wall plug to this? It will not have firm hold unless it has stud in the middle but I think only horizontal in the middle. I would try to use hollow wall anchor like picture below. The plastic anchor is easy to remove. The metal butterfly anchor one once you install the wing part will fall behind wall once you unscrew 

[attachmentid=10827454] [attachmentid=10827455]

There are probably more than 10 hollow wall anchor. Probably only few can easily be found on Malaysia. They are designed mostly more on specific load bearing. This is not only the winged type and in ideal situation the wing is flat to the inner wall for maximum grab but in general it is still designed for certain wall thickness. None is too specific thickness. Some type are just splitting the side just to provide grab. Don't even opened flat. It is still proper installation for their designed load. Like you said, you cannot screw it indefinitely since it is even plastic.

For this winged type you can find for other wall thickness also but it is hard to find. It will be applicable to a range of thickness, not being too specific.