if your talking about the team rocket uniform that's under ground in goldenrod (the place where you get accesories for your Pokemon)
you can't
Go the the radio tower and talk to the grunt guarding the satircase
you have to go to the underground where the dude takes pictures of you in a Team Rocket uniform. There will be a Team Rocket grunt who is looking for recruits. He will give you a uniform.
no you can trade soulsilver pokemon to black
Most likely, you are working in Goldenrod city to defeat team rocket, and your answer is once you get inside the radio tower, you will try to go up a flight of stairs, and your arch enemy will walk up and recognize you. You reveal your real clothes, and you will have to start fighting team rocket again.
he is not in Pokemon soulsilver or Pokemon heartgold
POKEMON SOULSILVER come with a poke walker and the Soulsilver game
Pokemon soulsilver and Pokemon heartgold are basically the same game just different versions but i do recommend buying Pokemon soulsilver
SOulsilver
go to goldenrod city and go to the underground tunnel a look around and there is a team rocket grunt there he will give it to you
You CANNOT LEGALLY download Pokemon Soulsilver.
You can't catch bastiodon in Pokemon soulsilver.