The skin.ini file most likely contains a line which specifies where the assets should go. Check the [Fonts] section for them and put the assets inside of that directory. The last part of that line is the file name, which can be freely changed. So if the line look like this: ComboPrefix: Fonts/Combo/numbers, the files would have to be named numbers-{#}.png inside of the Fonts/Combo/ directory within the skin folder. But at that point you can just change that line to make it work however you want, but hey. May as well organize your files a little bit.