Are you saying you aren't using the boost::random::mt19937 specialization? Because it's there just for people who don't have the background to choose an appropriate parametrization (like me who don't have a PhD on random generators).
typedef mersenne_twister_engine< uint32_t, 32, 624, 397, 31, 0x9908b0df, 11, 0xffffffff, 7, 0x9d2c5680, 15, 0xefc60000, 18, 1812433253 > mt19937;
Júlio.