mod_perl startup script and logging

[tomcat]

Hi.
Linux Debian
Apache httpd 2.4
mod_perl 2.0.9

...
PerlPostConfigRequire "/etc/apache2/modperl2_startup.pl"
...
modperl2_startup.pl contains the usual "use" directives, including
  use Apache2::ServerRec ();
  use Apache2::ServerUtil ();
  use Apache2::Log ();

If in this script, I would like to log something to the Apache server log (error_log), how 
do I do that ?
(I mean e.g., how can I get the server object, from inside modperl2_startup.pl 
?)