What function is in charge of keeping wordpress shortcodes between switching views?

I changed core files (until I find the way to re-define the functions with some sort of plugin) to render divs instead of DL's for captions in TinyMCE's js file "wpeditimage.js" and now when I switch back from visual to text view, the image is taken out the caption shortcode. The caption is put after the image every time I switch views.

I thought it would be some selector or regex still looking for a dl, and not finding it… but I don't even know what function is in charge of that matching/syncing.

I changed successfully the php code to render the front end code, but here I'm trying to accomplish the editor to render different code, in the editor (which uses JS, not PHP)

Thanks.