Oh, so you got themehax working. Did you update your 3DS or manage to get Rumble World updated without updating the system?
You need to add SVDT (Save Manager) to your programs on your SD card. It will contain its own folder just like the programs that came pre-installed if you downloaded the starter package. Once it is copied to your card, run themehax and launch the save manager. You might be confused at first because it won't display much information. You'll be staring at an icon for System Settings, and you must scroll left or right with the D-pad until you get to Pokemon Rumble World. Once you see the correct icon, press A. It will then take you to another screen where you have 3 options: Press (A) to copy the save to your SD card then Press (X) to exit. Turn off 3DS and put SD card pack in computer.
There will be a folder called "savedata" or something along those lines (sorry, don't want to pull my card out right now) and inside that folder is another folder called "00slot" or something similar. BACKUP that folder! Now use the Pokemon Rumble Save Editor to open the 00slot folder directly on your SD card. Edit it however you wish and save it back to the SD card.
Put the SD card back in the 3DS. Run themehax, save manager, and get back to the Pokemon Rumble World icon and open it. You will have the same three (3) options. but this time you need to press (B) to import the save. This will copy the save you just edited on your computer back to the game. Now, you can run Pokemon Rumble World again and see your new save.
Important Note: DO NOT run the game at any time while you're doing this. Only run it after you have copied your edited save back into the game. The problem is that every time the game runs it generates a new security code. So don't edit old saves and copy them. Only edit your fresh save and don't open the game until you've copied it back to the 3DS. If you do open the game, you will need to export it AGAIN. There are ways around this problem, but for now, you should stick with my advice.