HTTPS Working, HTTP Page NO -not found – 404

Hi,

On my VPS I have Centos 6.3 with cpanel.
I’ve buy recently a SSL certificate(RapidSSL), after I installed the certificate.
When I access my domain with HTTP I get:
http://www.MyDomain.com/cgi-sys/defaultwebpage.cgi
If I try to access a custom page(with HTTP) I get page not found -404.

But IF I access the DOMAIN OR A PAGE with HTTPS everything is OK and working.

I’ve installed the plugin: http://ww.wp.xz.cn/extend/plugins/wordpress-https/

the plugin working great, switch to HTTPS only the login and desired pages that is great too BUT of course what is not redirected to HTTPS and is redirect normal to HTTP all pages are not found(404)

For 2 days I Google’d, read topics, solutions but no solution for me, so interesting HTTPS working but HTTP NOT!

Can someone help me please, I’m stuck.

10x in advance!

P.S

My default .htaccess is:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress