There were some small changes to the file for the 2.0 update. I had a similar problem with the nav not loading up with the modified navigatemap file. I fixed this by taking the new version of the file and adding in the appropriate lines of code. Attached is my navigate map file which works perfectly for me.
Edit: Also, you shouldn't need the empty button image file, just the other two. Also, make sure that you are using a program like 7zip so that you're never actually extracting and repacking the data.zip file. With 7zip you can work with, browse, edit, and inject the data.zip file without actually ever unpacking the whole thing.