Ok, just tried it and love it, though I only got one song to work (out of 5), will look into this in a minute.
Ok, you can put the DsDsR.nds file anywhere, the DsDsR FOLDER however, need to be in the root directory. In the songs folder make a folder for a group (call it whatever you want), then in THAT folder put the songs (which are in their own individual folders too).
It only reads sm files for the steps and mp3 for the audio, I have a feeling it didn't like that some of my songs had dwi and sm files in their folders.
You may have to DLDI patch it to, I didn't have to on my R4.
God, I need a new flashcart just so I can fill up a SDHC card with this.
edit: hmm... I removed the dwi files from the songs that didn't work (leaving the sm files intact) and they still don't work. Not sure what the problem is, I'll do more tests later.