autoconfig, howto use autoadmin.global_config_url

hello,

I really appreciated netscape 4.XX autoconfig feature. Now I want to 
upgrade to mozilla 1.2.1 and I can still use those great fonctions 
(getenv, getLDAPAttributes ...) from prefcalls.js by adding the 
following line in all.js:
  pref("general.config.filename", "mozilla.cfg");
Using tools (moz-byteshift.pl) from 
http://www.alain.knaff.lu/howto/MozillaCustomization/ we can generate a 
common preference file based on env variable or ldap queries in order to 
personnalize mozilla to the user who is logged in a shared station (very 
usefull on campus), great !

now with netscape 4.XX there was a keyword: autoadmin.global_config_url 
wich allowed me to even more centralized configuration, by putting the 
preference file on a web server . I cannot use it anymore :-(

althought I put in config.js the line:
config("autoadmin.global_config_url","http://corbeau.int-evry.fr/browser/config-ldap-ns.js");
The http server did get the request when mozilla is launch by a client, 
but nothing inside the files seems to be executed !?

Any help on this feature (autoadmin.global_config_url) and how to use it 
will be really appreciated .

Thanks.

PS: here's the doc I wrote about using this feature in netscape 4.XX (in 
french ...).
http://www.int-evry.fr/mci/user/procacci/netscape/netscape-autoconfig.html