To configure Apache 2.2.3 with ssl, it is mandatory to have mod_ssl.so
compatible with this version.
Someone knows where I could find the compatible version of mod_ssl.so, please.
In order to have mod_ssl to work, you also have to use an SSL compatible version of httpd binary. I cannot guarantee you that EasyPHP is bundled with Apache-ssl. Better than downloading a separate mod_ssl.so, I would advise you to download the full Apache httpd 2.2.3 with ssl compatibility package and upgrade your current EasyPHP installation.
Anyway, remember EasyPHP was not especially designed for SSL support.