Custom symbols in reminder text

I have sucessfully created some custom symbols for my cards, by editting them in the "magic-mana-small.mse-symbol-font"-Folder.

And then add it to symbol-font folder there.

for example

symbol:
code: *C
image: Trigger Combat.png
image font size: 200

I have than also edited the

# Insert-symbol menu

but it didn't worked, so i assume i should do that in another file.

I would very appreciate your help on this subject