Our software update is now concluded. You will need to reset your password to log in. In order to do this, you will have to click "Log in" in the top right corner and then "Forgot your password?".
Welcome to PokéCommunity! Register now and join one of the best fan communities on the 'net to talk Pokémon and more! We are not affiliated with The Pokémon Company or Nintendo.
I think you can just change the song in the MetaData without having to replace. If you're looking to replace a song in a game that you didn't make, you can convert files just by renaming them, and changing a .MP3 to a .MID shouldn't change the quality of the song. (Well, it doesn't for me anyway.)
Just look up "how to change file type by renaming" and whatever type of computer you're using. (I dunno if this works for Mac, however.)