How to map secure.domain.com to www.domain.com or domain.com with "WordPress MU Domain Mapping" on the primary multisite domain?

Question

We have a multisite setup, the primary site needs to have example.com, www.example.com and secure.example.com mapped in wordpress so the primary site's content loads on them.

secure.example.com will be over HTTPS.

The problem we are facing is everything except secure.example.com works. When attempting to access https://secure.example.com there is a 302 redirect to: http://www.example.com/wp-signup.php?new=secure.example.com secure.domain.com has a SSL Certificate to server secure content. Obviously it can't just redirect otherwise it wouldn't be secure any longer.

WordPress MU Domain Mapping is installed but doesn't appear under the primary site's menus. When trying to access the plugin directly via ~/wp-admin/tools.php?page=domainmapping we recieve the message

"You do not have sufficient permissions to access this page."

Note: We are logged in as Super Admin.

Any suggestions regarding to this would be highly appreciated.

Answer 1

In the end I ended using mod_rewrite through .htaccess. The following is what I am using and so far is working well.

RewriteCond %{HTTP_HOST} ^secure\.domain\.net$
RewriteRule (.*) http://www.domain.net/$1 [P,L]