Breeding eevee and ditto in pokemon soul silver?

Even if they don't like each other, you'll still get an egg. With your bike, go up and down Goldenrod for about 5 minutes. Then, the old man from the daycare will call you, or you can just talk to the lady in the daycare and she will tell you if you got an egg. If you didn't, just keep riding your bike up and down and you'll eventually get it.