Category of problem: Extension   PrefSwitch

Mediawiki Product Version MediaWiki 1.18.1 PHP 5.3.3 (cgi-fcgi) MySQL 5.0.51a-24+lenny5-log PrefSwitch (Version 0.1.2) $wgDefaultSkin = "vector";

Extension Installation instruction followed: http://www.mediawiki.org/wiki/Extension:PrefSwitch http://www.mediawiki.org/wiki/Manual:Update.php

Problem met: Although the extension is installed, and php restarted (locally with a terminal, and hosted via web process), the extension does not appear at all. Only the standard vector MediaWiki 1.18.1 edit tool is present when editing.

Question: What should we do to make the editing tools menu used by mediawiki's wiki, appearing and working ? Isn't it PrefSwitch which should make this editing menu working ? Why the extension installation process really strictly followed of PrefSwitch does not work ? Should we install something else ?

Thanks for your help