Accessing Dream World in Pokemon Black?

Alrighty, I have major issues with this (that's what happens when the most advanced thing your favorite Pokemon game is enabled with is a wireless adapter... That's right, Pokemon Leaf Green, all the way.) I'm hearing something about Musharna and Dream Smoke? I have the Pokemon Global Link account and ID registered, and I'm able to tuck Pokemon in, but I'm only able to obtain Dream Remnants and for some reason cannot figure out how to actually access the Dream World. Help?