I almost forget the initial purpose of this tool is to import SMS from other phones, instead of do backup and restore on the same phone.

It's because the official tool commhistory-tool might be more suitable for that.

You can download it from http://wwwjfy.net/tools/commhistory-tool
Don't forget to run
chmod +x commhistory-tool
to add execution permission

the usage is similar:
./commhistory-tool export filename
./commhistory-tool import filename

The only disadvantage is the exported file is a binary file.
Also I don't own the phone so I don't have much time to try it out. I'm sorry if anything wrong happens, and as usual get everything backed up first.