I'm talking from memory, but it's a basic procedure.
Get ShowMiiWads, open it up with the WADs on the same folder as the program. You'll see them on the list when ShowMiiWads load. You right-ckick one of them and choose to Extract > Folder.
A folder will be created wherever you choose, with the files of the WAD. Go to it and you'll see all the .app files. Open 00000001.app with HxD. Now press Crtf + F for Search, select the tab "Hexadecimal values".
Copy "80 04 00 04 2C 00 00 FF 40 82 00 10 80 04 00 08 2C 00 00 FF" without the " and click on search. HxD will look for the string of values, and should find it very quick as it's a small file. Once it finds it, it will show it to you. From there, follow the values backwards until you find "94 21 FF E0" not too far back.
Once you do, you click on 94 and write 4E 80 00 20, basically overwriting 94 21 FF E0. You can just click and drag to select 94 21 FF E0 after you find it, and paste 4E 80 00 20 over them. Once you do, you save and cose HxD. You only need to repack the WAD, which you can do with ShowMiiWads again, it's undet he Tools section.
Then you're left with a WAD file with the changes, which you can install and try.