How to get custom kits to work?

Hello:

I'm having trouble getting some custom kit mods to work. They seem to install just fine, and appear correctly when creating a character, but are unselectable. I've been browsing the forum for awhile and can't find any explanation on how to fix this that doesn't require me to have an extensive knowledge of editing various text files and using various command prompts that I do not at all understand.

Is there a fix for this? Can someone point me to an explanation that a novice to modding would understand?