Rails - Aug 2009 - Continue to use assets functions on a different host and path ?

Hello,
I just build my new Rails application, i placed the website like
that : at

http://www.***.net/ = /var/www/devkedare/public/ (with mod_rails)

http://media.***.net/ = /var/www/media/

I want to use the javascript :cache features, the "timed" files to
prevent caching when file change (ex: x.js?1249517571), and all others
greats files features,
I configured the asset_host to use the media domain, and it work, but
how to tell to rails to use that directory (/var/www/media) and no /
var/www/devkedare/public/ like how it do and to continue to use all
the functions that it provide when the files are places at public/
Is there a way to do that ?
Thanks :)

Sorry for my bad english