Modding Custom Number Textures in Uniforms

[Andrew]

I've prepared my uniform textures and correctly placed the number areas, but I can’t seem to mod in my own number texture. When I launch the game, the number section just appears blank.
Can anyone explain how to successfully add custom letter/number arrays into the game?
Also, as a side question—though not urgent—is it possible to use two separate number arrays on the same jersey (e.g., one for the front and one for the back)?
I’d really appreciate any help or guidance!