Odds are, if you're a programmer, that you'd have come up with a very similar scheme, given knowledge of the kinds of messages the software is expected to send or receive. I.e. leave the envelope plausible-looking and stash the payload in the random-seeming bits.
Although not a professional programmer, I do agree with what you said. But the whole scheme also includes execution on other fronts (e.g. how did they plant the payload).
