Thanks Martin for your valuable hint - I think this is the way how it is implemented. PTC should explain in details in HELP how this rule works. My reasoning is that win_font will use current Windows system font, while ttf_font is just example how to convert any ttf font into PTC font.
I did an example and it is working as you pointed. When user will put to installation folder:
Creo4_M0XX\Creo 4.0\M0XX\Common Files\text\usascii\fontname.ndx contains following lines:
WANTEDFONT.ttf
special.fnt
this will install WANTEDFONT.ttf as fontname, but .ndx file need to be edited in e.g. Notepad++ or other editor but not in original Windows Notepad, because there is something about end line coding and after just editing even current .ndx files they will be corrupted and fonts disappear from the list ;-(
Important thing: please remember to put WANTEDFONT.ttf into following folder:
Creo4_M0XX\Creo 4.0\M0XX\Common Files\text\fonts
Thanks Martin for your help and directions!