Oblivion exporting animation files .kf

[overdev]

Hi

I need to modify an existing custom animation but the issue is the export.

blender 2.92 with the ported niftool addon doesn't properly save the modified animation as a .kf file. the file is much smaller (2 KB instead of 7 KB), creating a new scene, importing skeleton and animation doesn't show any animation at all. Is there any setting I need to change? Everything I've done is "export .kf only".

I also tried this ancient complete package of Blender with old nif tools: https://www.nexusmods.com/oblivion/mods/42755

When I import the saved kf file into the new blender the animation works except it seems like one arm doesn't move but it does nothing ingame.

Is there any proper way to save those kf animation files?