How do you get a baltoy in Pokemon Pearl Diamond or Platinum?

its completely random actually talk to the girl in sand gem after you do the stark moutain event and all that stuff after words, she will tell you when ther are Pokemon outbreaks, some of them include, beldum,natu, and even baltoy, you can also catch baltoys by, inserting ruby Sapphire or emerald into the gba advanced cartridge if you are not using a D.S light and your using the D.S.I i am sorry, those are to complicated for me to explain ( i haven't gotten my cartridge for it yet to really try)

-king rampardos-