Using a J2EE Server Component -> Library

Hello everyone:

I needed to include some jar files in my WebDynpro project, so I created a new J2EE Server Component -> Library and added the jar there in the Java Build Path -> Add external Jars.... so I successfully deployed the library in the server.... I heard that was enough to set the required jar file into the server.... but now, how can I get to "use" it in my deployed webDynpro app? I get the classNotFound thing.... how can I reference it? I can't get to do it, I think I'll end uploading the jar file and setting it in the server CLASSPATH =(

Thanks