Hello!
If anyone out there already dealt with this specific file format, I'd gladly like help. There are a few licensed (or downright shovelware) DS games which had their OST composed by Allister Brimble. Two examples I have handy are the games "Tootuff: Mission Nadia" and "Astérix & Obélix XXL...
Cruisn on the Wii is one of my personal examples of that, it's considered one of the worst games of all time, I loved it and completed it several times.