Hi jorfermo;
So is the frontend a slave of the backend, or is the backend a slave of the frontend? With your command, you would be syncing what is on the backend to the frontend. The fact that your destination table is empty leads me to believe things are reversed from what you you are intending.
One thing you can do is use the --print option instead of --execute to see what it would actually be doing. That tends to help get your mind around what is happening.
-Scott