I'm not sure why no one has answered your question.
One reason might be that it sort of gets the "cart before the horse". Music, timed to do the "42 step", depends entirely on how fast you do the "42 Step". Most people, and properly, do thier Taiji, qigong, or whatever, to the timing of thier breath. How fast do you breathe?
I suggest that you find some music to your liking and do your "42 Step" according to your breath, while you listen to your music. When you are done with your "42 Step", turn off the music, or listen to the end, as pleases you.
You might also consider doing your "42 Step" according to your breath, but concentrate your thought on precision while doing each step. You'll be surprised at how little you miss the music.