Borderlands Pre Sequel - editing font to subtitles

[BoleronUrk 0]

Hello,

First of all, sorry for writing in English, but I don’t know Russian (I’m from Poland).
Here is the thing. I wanted to add/edit font so game will show Polish special letters. Using Brdr2Fonts.upk from Russian fan translation, HxD and JPEXS Free Flash Decompiler, I was able to add Polish special letters to the game (at least Interface), but problem occured in subtitles. Instead of Polish letters I have squares which is weird because WillowBody font works good with UI and on items etc, squares are only in subtitles.
I was been told that font in subtitles is in another file. I found it in Startup_LOC_INT.upk. There are some files like font_willowbody_18pt.Font and Font_Willowbody_18pt_PageB.Texture2D, Font_Willowbody_18pt_PageA.Texture2D, but I don’t really know how to edit them.

Can someone help me?