I don't have a BMS script but you can use two other tools to achieve the result you want.
I used these settings to get it to playback correctly using vgmstream thanks to VGMToolbox by adding a GENH header to the DHX audio file.
Here are the settings you need to set in VGM Toolbox:
Input: PlayStation 4-bit ADPCM
Header Skip: 0x800
Interleave / Block Size: 0x800
to create the GENH file/s from the DHX files.
Then use vgmstream
to playback/convert them into PCM WAV.