Ok, here it is:
class CfgMusic
{
tracks[] = {ST_1};
class ST_1
{
name = "ST_1";
sound[] = {\music\ST_1.ogg, db + 0, 1.0};
titles[] = {0, ""};
};
};
Still no effect. No ST_1 track in the Tracklist. Any track from the list plays correct.
UPDATED: I found the reason! I placed .ext file in the wrong mission folder, so it was a matter of attention. Nettrucker, thank you very much. :D