Installing and upgrading help

Hi,

I've recently set up Moodle 2.6.2+ on a Nginx webserver in Debian Wheezy. After following the Nginx specific howtos I was able to resolve all initial problems and when I access Moodle through  http everything is as it should be but as soon as I try https  the login screens looks garbled  similar to when I had before switching 'slasharguments' from 1 to 0 on http and when I try to log in under https I get a warning message that the login data will be transfered unencrypted even through the page itself is ssl encrypted.

I'm using exactly the same php specific lines in Nginx for http and https and I'm wondering if anybody has a clue for me on what I could have missed regarding accessing Moodle on Nginx through https

Thanks for any hints