Can you change the world type on an existing world in Minecraft?

I play mine craft with the Walking Dead Mod, I want the custom zombies that come only with the custom CD Cure world type but I also want to use my custom map. Is it possible to change the world type on my map to this custom world type?

PS: 10 points for the first person to help me with this.

Guest

Once you create the world, All you can do is change the difficulty, You can't change the world layout. Sorry.

Hope this Helped.

hhahafunny