The rusty padlock went green quite easily !
Just like everyone of you, I was excited about the SSL coming to WA platform, and (un) like you, I found it was harder than just pushing a button. The padlock wouldn't go green!
I read a lot about issues and how to fix them here at WA and elsewhere, I tried many plugins (WP Force SSL, SSL Insecure Content Fixer, Search and Replace) to no avail!
Then, after some digging, I found that the theme I’ve been using was to blame! I just changed it, chose a clean and lean mag theme, and voilà!
As green as fresh grass…
Now, I'm not sure what's next :) I heard something about verifying the HTTPs version of the website. Hope you're doing better than me :)