Well, I seem to have figured it out.
insane?
const int c_difficulty = 0;
const int c_mineralBonus = 2;
const string c_maphack = "false";

very hard
const int c_difficulty = 0;
const int c_mineralBonus = 1;
const string c_maphack = "false";

hard:
const int c_difficulty = 1;
const int c_mineralBonus = 2;
const string c_maphack = "false";

medium:
const int c_difficulty = 1;
const int c_mineralBonus = 1;
const string c_maphack = "false";

easy:
const int c_difficulty = 2;
const int c_mineralBonus = 2;
const string c_maphack = "false";

very easy:
const int c_difficulty = 2;
const int c_mineralBonus = 1;
const string c_maphack = "false";

Anyone know how to make a custom difficulty that wont be affected by the launcher setting, and how it will affect ladder? I'd like maphack enabled (to simulate a skilled player scouting) and 0 difficulty and 1 mineralbonus.