How to upgrade Objects to version 4.

mestre

Hi,
I need to upgrade one Navision DB from 3.60 with customizations to 4.00.
I already get the developers toolkit, and imported the Nav 4.00, the 3.60 without customizations and the 3.60 with customizations. But after I did that, I read in document about upgrading that I should remove the IDs from the files. I already did that, my doubt is, do I have to delete in developers toolkit all the DB’s except the 4.00 version and import with this files without IDs, or in merge wizard when it asks me the file of the respective versions, I just indicate this ones.
Thanks in advanced.