Yeah, I did.
1. I opened the texture pack.
2. I pressed edit to open the individual skins.
3. I found steve, edited it like in the tutorial on the site.
4. I saved the changes to steve's skin.
5. I went to the top of the page and pressed deploy.
6. Waited a bit, reloaded. It said deployed.
7. Back on the texture pack screen with the instructions to put in my code, I copied that code directly into my mod. (Skins don't look edited on this screen. They look like originals.)
8. I launch the server, mod, etc. I execute the command, and it tells me it's going to install a custom texture pack. It does, but nothing changes.
It looks like I did everything correctly, but I might have missed a step somewhere?