All browsers: Cant get connected to some SSL pages?

[airplanesimen]

Hello all!

This time, i am going to solve some irritating things with my networking on school, using ubuntu 12.10.
I am perfectly able to connect to the proxy authenticated network the school uses. But my problem is something else; I am not able to access for example gmail.com or any ssl secured log-in pages. And where i am able to, i am not able to see any of the layout (f.ex. facebook) because the secure content is blocked.

The thing is, i am able to connect to all those pages at home, but i am not able on the school proxy.

So, could it be the proxy blocking the ssl connections, or the ssl certificates? And i am able to reach those pages from windows without any problem.

Let me take an example for you:

I open my browser, and the homepage is set to www.google.com, where i am usually logged in as a Google-user. That would mean, https, and it's secured. The browser asks me to put in the proxy authentication details, and then it warns me: Security certificate is NOT trusted!.
And i just click "proceed anyway" x2, and then i am able to go into google.com.
For Gmail, i am not able to see the "proceed anyway" button in chrome. It just says: "back to safety". In Firefox, i am not able to make an exception for the page either..

So, is there any way how i can access those pages from ubuntu, and not only windows? I am a huge fan of ubuntu, and i have used it for a long time. So ANY help will be great!

Thanks for reading, and i hope that someone is able to help me with this!