if you mean if you lose just talk to him again or her but if you win and you want to battle again you cant
You cannot battle between a Pokemon Black game and a Pokemon Soulsilver game.
No.
No, but you can import Platinum Pokemon to Black.
No they can't.
No
No
Just to the left of the Pokemon center in Opelucid City. It's called the Battle House in Pokemon black and white.
no
no
No.
Yes
from the janitor after you defeat him in a pokemon battle in the battle tower in castelia city in both pokemon black and white versions.