new properties

I have to use some application's parameters in my pages.
So I create a new propertie file, and I would like to read this file...
 
The first idea is to read this file at the beginning (with
ResourceBundle class for exemple) and store the result in the session ;
but I don't know which resource is called at the beginning (when i try
to connect tu the site). Most of users of my site don't autentificate
themselves... they are "guest".
 
Another solution would be to add properties to jahia.properties but how
can I read them ?
 
 
Alexandra Bohy