Deploying BIRT WebViewerExample in Tomcat 5.5

When deploying the WebViewerExample of the BIRT runtime as documented, the viewer application didn't start correctly but gave a java.security.AccessControlException: access denied (java.io.FilePermission /var/lib/tomcat5.5/webapps/birt-viewer/documents
write), because it couldn't create the documents directory in it's installation directory.

Some googling showed that the problem was that in Debian/Ubuntu Tomcat is started using the java security manager. The solution given was to deactivate the security manager in /etc/init.d/tomcat5.5, but that didn't quite convince me. I simply granted the web application all permissions by appending to /etc/tomcat5.5/policy.d/50user.policy:

grant codeBase "file:${catalina.base}/webapps/birt-viewer/-" {
    permission java.security.AllPermission;
};