SoX with special filenames problem

If anyone here uses SoX which is a CMD utility, I'd appreciate it, if you might know how to fix it with special filenames.

Link to page:
Download link:

Below won't work: Save below code as .bat file, change necessary paths and run in CMD

rem Point sox.exe to path and change other filenames also to test.
rem Sox has problem with special filenames.

set SOX="Z:\Music\Programs\_Portable Installs\SoX\sox.exe"
%SOX% "C:\Лезвию.wav" "C:\test.flac"

SoX is open source AFAIK so maybe someone here may know how to fix it.