ok you where right, i need a line printer config --on the print server--
and _eventually_ an driver/filter config on the client.

It works now.

I don't understand why i can't keep a driver/filter config on the print
server and just use a line printer redirection on the clients btw (this
would be much easyer for clients configuration, if there are lots of
them, and if they don't have the latest ghostscript drivers for example).

Anyway, thanks for you help, which was usefull.
-- 
Pierre-Philipp