[OS X Emacs] LaTeX-section-label customization

[kbmail at free.fr]

Hello,

here's my problem: I'd like to get prefixes ending with "_" instead  
of ":" (like "sec_" instead of "sec:", idem for "chap_", "fig_",  
"eq_", etc.) when using C-c C-s, because the [french]{varioref}  
package isn't happy ":"... (I also renamed fancyrefargdelim with "_")

I succeeded in changing all the prefixes via the aquamacs  
customization interface, in saving them and reopening them.
But C-c C-s still gives me ":"...

Then I directly modified the "latex.el" file to rewrite all the  
prefixes with "_" at the end, and you know what?
C-c C-s still gives me ":"...

I'm tired to erase "_" and rewrite ":" each time I invoque C-c C-s,  
so if you know how to automatize it, it would be great!

Cheers,
Karim