well i don't no the real answer but i have tried you could always just go do like the race things or whatever that coliseum thing i have tried to past the time but you could always chat with me name Hosh13 come talk to me on my message board.
When you change your DS's time Soulsilver/Heartgold automatically changes to the DS's time setting. You can check the Pokegear's clock.
At Route 45 and Mt. Silver, but they're hard to encounter
There isn't any anti-freeze code on Pokemon SoulSilver or HeartGold at this current time being.
It's been quite a long time.. But I believe you go down the escalator in a Pokemon center and talk to the lady in the middle.
route 38-39 its where i find them all the time. (for proof i looked in my pokedex to make sure