linux / tomcat

[Faillot]

Hi, 
I have a Java servlet running with Tomcat 5.5 under Linux Debian. 
I need to indicate tomcat where are located the other processes called
by the Java servlet. For that, I must specify environment variables for
the tomcat user (and not for root or any other user) and for my specific
webapp. But I don't know in which configuration file I need to do that.
Do you have any idea ?
Many thanks, 
M