ZT230 and CP852 characters


I need to print files with CP852 encoding (czech single byte) characters on Zebra ZT230. I downloaded TTF fonts I want to use to the printer, I have JIS.DAT (in printer), which  is said to be for CP852. But the JIS.DAT looks like conversion from 2 bytes to 2 bytes characters, not from single byte to unicode (for the TTF fonts). I tried many combinations of settings, but czech characters are not printed correctly (unless I rewrite the text to unicode, which is not option for production). It seems I am missing something important.

Any help, please?

Thank, Michal