in pokemon soul silver how do i get to blackthorn city

[Togepi]

can someone direct me on how to get to blackthorn city on pokemon soulsilver

[Galaxy]

go to radio tower in goldenrod city and a rocket grunt will tell you only people in cool rocket uniform can get in so now go to underground passage in goldenrod find rocket guy near camera tell him you are a new recruit and he will give you uniform then go back to radio tower and beat the team rocket guys and youll get access to blackthorn city