Thank you jonwil for taking the time to look into this, it would have taken me a lot more time to find it by myself.
Now I have to see how I can manage to edit the librtcom-presence-ui.so file ; if it is even possible.

BTW : what is your method to find these informations? Do you simply look for everything that seems to be related to what you are looking for and try to understand the logic behind it? How did you even know that some info is hardcoded in librtcom-presence-ui.so (I opened it with an hex editor but it looks like a foreign language to me).