How to add a custom kit mid-save in FM24?

Hi everyone,
I'm currently playing an ongoing save in FM24 where I created my own custom club and added some friends to build a 26-player squad. Since the club was created from scratch, the kit is just the default generic one from the game.

I’d love to add a custom kit to make the experience more immersive, but I’m not sure how to do this in a save that’s already in progress. I do have a licensed FMRTE24, and I’ve been able to change the basic kit settings available through the app — but those options are pretty limited.

Is there any way to add or replace the kit graphics mid-save? Do I need to edit any config files or use external tools for this to work properly?

Any help or guidance would be greatly appreciated. Thanks in advance!