Wordpress login on subdomain of non multidomain installation over SSL

view story

http://serverfault.com – I have the following setup, a one domain installation of wordpress 3.7.1, I'm using force ssl admin and this woks fine. I'm using Apache 2.2.2 on Ubuntu 12.04 LTS. I have set up a subdomain admin.domain.com which I would like to be the wordpress login over SSL. I'd like to not allow access to the wordpress login at all through anything other than the subdomain. I'd also like the root of the subdomain to go straight to the wordpress login. When I point my subdomain via DirectoryRoot to the wp-admin folder, then I'm sort of halfway there, I go straight to the login screen but the previews and (HowTos)