ROM Hack Can ExData be obtained on a computer without SaveDataFiler?

[JohnTravolski]

Here's the deal. I have a friend who wants to record Pokemon Wi-Fi battles for other people. The problem is that, as far as I know, the ONLY way to change the battle backgrounds is to have SaveDataFiler installed on the system so that the battle videos can be edited on the computer, because SaveDataFiler can do that by exporting the ExData (where the battle videos are saved) to the SD card. However, from what I understand, the Battle Videos are saved on the SD card in the first place. So, with that knowledge, would it be possible to for this to happen:

1. Somebody else (who does NOT have a hacked 3DS at all) sends the regular data on their SD card with the battle video saved on it to my friend.
2. My friend, who does have a hacked 3DS, somehow uses some program on the computer to create the same effect (which is using SaveDataFiler to export ExData on to the SD card) (basically make it in the usable format).
3. My friend changes the battle videos' backgrounds (which is easy).
4. My friend puts the necessary files on his own SD card and then uses SaveDataFiler to get the edited battle videos into his game.

The real question here is how much of this ExData stuff is stored directly on the system (not the SD card) in the first place. He needs to be able to transfer somebody else's battle video to his own system.