OK, I was stuck on 99% and only needed 4 clothing-items (which come with the suitcase, on the place where you stranded the first time). I played for hours on end, but the suitcase never came (only the crate, or other items like sticks or leafs I didn't need!).
Here's how I eventually got what I wanted:
1 - First thing: play around until your energy is quite low and go to sleep in your shelter. Save your game.
2 - Wake up and walk to the beach (1 click to the right). There should be an item or a crate now. No Go back to 1.
3 - If the item you need IS there (on the beach, in the crate or in the suitcase...): play on! If you need something else badly, you can go back to 1. (don't forget to Save!).
4 - The item you need isn't there: press the "Start" button on your NDS and select "Quit" and "Yes".
5 - Select "Load game" and then select the game you previously saved. Go back to 2.
The item you get, seems to be given at random by the game. So you may need to repeat the steps above a lot of times. I noticed that the suitcase comes every 10 to 20 times! I spent an hour, getting the 4 items I needed, but now at least I have 100%!
Maybe this trick also works with the parachute, but I have not tried that...