If it is SSL (https) then there is a certificate.
Go to the https link on you pc. Depending on the browser you will see a padlock in the bottom corner. Double click it and under the details tab copy to file. This will start an export wizard. Choose Base-64, click next and name the file something.
Connect the Pre to the pc as a usb drive and transfer the file.
Come out of usb mode and in the Pre under Device Info go to Preferences (up top) and select Certificate Manager. You should be able to import the certificate from here.
It may not help, but it can't hurt.