Nope its not the same. You export all the data, and import it again, that resault in replacing all the other datas.
The way I do it: (sorry if you misunderstood me, im not that good at english)
1. I will import the data to the campaign editors object editor
2. Then I will open the map and open the object editor (not that in the campaign editor)
3. Then you can simple copy&paste through the two object editors.
You get what i mean? if not, I guess I have to upload some pictures or a video hehe..