I'm wondering if there is a solutions to store, respectably to camouflage data into music/sound (so that a convert to another music format [mp3] should not bother it too much)?
Back in the older days I stumbled around a tool which saves any data into a picture. It not only add data to the end of the file or something, it combines the files.
What you want do is a steganography process and the software you refer to is certainly "Camouflage".
Here you can find a list of steganography software. For your purpouse I suggest "Data Stash" or "MP3Stego".