MK12 Font editing

[art-kandy]

Hi,
I'm trying to modify MK12 fonts (for adding characters from my native language). And I see several issues:
- editing the SWF file, stored in GFxUIFonts.uasset. As I understand developers used Scaleform GFx and some custom plugin for it in UE4.
- putting it in .utoc file, as the existing EU4.27 version doesn't support SwfMovie type.

For now, I'm trying to focus on 2nd issue (patching), cause SWF editing could be done in JPEXS Free Flash Decompiler. And here I have other issues. I'm trying to pack GFxUIFonts.uasset using the tutorial for models and textures, but UE can't recognize uassets received from FModel or UModel cause they don't include PackageFileSummary section. Hence I've got the "malformed tag" error.

Has anyone tried to patch using raw assets in MK12? Or dealt with GFx fonts? Could you help me?

Thanks.