Is anyone familiar with the .SSQ file format? (DDR iPhone)

[Goldenwind]

I've gone digging through the files on my iPhone, and came across something pretty interesting - the raw files used by the DDR app.
The music? mp3.
The chart? ssq.

As someone who's made charts for many, many years now, seeing the .ssq file was like a golden nugget. I always knew Konami had their own stepchart-making tool, totally different from StepMania, and I wanted to know how it was made.

So I open this little sucker in Notepad, AND!... it's in binary.
For the computer illiterate, this means it was just a bunch of random garble (Whereas opening a .sm file in Notepad gives you actual text and numbers).

Is anyone familiar with how to deal with the .ssq file format? I'm interested in reading what's there, as well as writing my own (Even if I have to type 0s and 1s - this is mostly experimental)

Edit: The above was referring to DDR S+
I looked into DDR Freedom, which seems to use .gen files to bundle both the chart and the music (As there are no mp3s here, and the .gens are 3-5MB). I'd also be interested in how to deal with these.