thanks for trying... nice link but that is not the point. datasource is well configured, this application works in my web container and now I'm deploying it into another tomcat container, but I can't access server.xml file. so, I'm using tomcat manager, deploying using context.xml file, did you understand?
Have you tried putting the context.xml in your JAR's META-INF directory? If so, make sure your XML's main tag is <context> and your docBase is modified to point to the working directory in the enviroment where your application is going to be deployed.