Can you trade a Kadabra, machoke, haunter, and gravler from pokemon leaf green and not make them evolve.?

I'm trying to fill my pokedex on black, and since you can't trade straight from green (first trading to platinum) i wonder how the Im going to get those middle evolutions in my dex. I also dont want to go through the annoyance of Breeding. Does any one know if you can cancel those evolutions? Because if So I'll just send two Kadabras over or something, and just cancel one.