Not very hard. They are simple steps :
1st - Go to object editor
2nd - Click (in the object editor) the File button
3rd - Click on Export All Object Data
NOTE : If the above is grey, it means either there is a bug or that u dont have custom objects in there.
4th - Save the Objects somewhere
5th - Open the desired map
6th - do step 1,2
7th - Go to Import All Object Data
8th - Wait for a bit unitl it downloads all
9th - I belive u finished
IF it doesnt work, u must do the same steps, but instead of exporting All Object Data, u must import each of them separatly.
U do the same for triggers.
Here are all the file types :
All Object Data <saved name>.w3o
Triggers <saved name>.wct and .wtg
------ I dont remember the rest... sry ------
i wish i helped.