Problems on SSL site…

Hi. I am using this plugin to integrate Amazon.de / Amazon.com advertisements in my blog. My website is running on https. However, when an ad from Amazon is displayed the users gets a warning “unsecure content on this page” and a warning sign on the certificate icon.

I tried asking Amazon about this but their first line support doesn’t have a clue what a certificate is or how their affiliate system works and I can not past these first-liners. Does anyone have experience with integrating Amazon ads on an SSL site?

Thanks in advance.