[CentOS] Localize CUPS?

Hi,

I've been setting up a networked printer in a 100% Linux LAN, and 
there's only one small problem left: how do I localize the CUPS 
interface (e. g. the pages I see when opening http://localhost:631 in a 
browser)?

My system is localized in french. LANG is fr_FR.UTF-8 in 
/etc/sysconfig/i18n. And I checked Firefox: it's supposed to open web 
content in French.

Curiously, I had done similar installs before with Slackware 12, and 
there, the CUPS interface displayed in french "out of the box", e. g. 
without specifying it in cupsd.conf. Now IIRC, I had explicitly set a 
whole bunch of environment variables on my Slackware install 
(LC_MESSAGES and the likes) to french. 1) Could it be that? 2) Which 
variable would that be, and where do I set these in CentOS? Slackware's 
localization variables are all meant to be set in 
/etc/profile.d/lang.sh. Where is the orthodox place to do that in CentOS?

cheers,

Niki Kovacs