How add custom hl2 & platform resources?

I make Polish translation of the game.
All working fine except resources from hl2 and platform directory.
Even if I add modified version of this file to my custom vpk or to Custom folder (I add search paths to gameinfo before any other search paths), game will load original files.
Only solution for now is replace or delete original files which I want to replace.

This is not elegant solution I don’t wanna modify/delete original game files.

This problem would not exist if game will respect polish language in steam interface settings.

Any ideas?