I would like to change the alert message sound from Facebook Messenger. It is saved under 0.wav. I've changed this file manually but would like to do it using a winterboard theme, so I don't have to repeat it everytime i update. I've tried it and it doesn't seem to work. I created a theme that changed the icon but the sound remains the same.

Does winterboard work for wav files? Or is this there an alternative way?

Thanks