Problem with adding musics to ZH Options

[Casojin]

I've tried to create a custom music playlist for Contra (since Creator makes it possible to use custom playlist) with partial success.
The music in Shellmap and Loading screen played just fine.
But the music in the game play only a few tracks while there are 15 tracks for each faction specified in Contra music.ini file.
China played only 2 tracks and GLA only 3 (I haven't tried USA yet) before the music went silent (I'm not sure whether it happens in original ZH too).
Is this the limit of ZH? Or is there another way to fix this?
I've been trying to find the source (I was looking at the ini files) for playlist and found none.
Any suggestion?