Well, i'm going to modify my hack in order to answer your request. What do you think to setup the picture to use by language id.
I mean in vBulletin options->Against Piracy Logo you will have something like this :
English image and text
Enter here the language ids you want to use english image and text :
French image and text
Enter here the language ids you want to use french image and text :
German image and text
Enter here the language ids you want to use german image and text :
If you're ok with that, i'll make it later (in a few hours, time for me to go back to paris, to sleep 3 hours and to go work and take an orange juice to wake up

The good news is that i've finished to write my paper

)
See you later.