Problem configuring rewrite rules for .htaccess

[JamieRW]

Apache/2.2.3 (Debian)
Control Panel Plesk
Environment Joomla 1.5.9

Hi,

I am having problems configuring .htaccess. The first rewrite rule for http:// to http://www seems to work fine but the https:// to http://www doesn't seem to.

I have 'Force SSL' enabled for the 'Administrator only' in Joomla but when I try and login I am getting thrown back to the login screen.

I'm wondering if these rules are conflicting somehow... can anyone confirm that this should work or suggest a fix.

Thanks in advance, DM.

--
########## Begin - Rewrite rules to enhance SEO SEF
#
RewriteCond %{HTTP_HOST} ^mydomain.com$ [NC]
RewriteRule ^(.*)$ http://www.mydomain/$1 [R=301,L]
#
RewriteCond %{HTTPS_HOST} ^mydomain.com$ [NC]
RewriteRule ^(.*)$ https://www.mydomain/$1 [R=301,L]
#
########## End - Rewrite rules to enhance SEO SEF
--