We are researching the IIS/ASP.net set up / configuration to have Safari & IE accept iFrames coming from a secured (Windows 2008 R2) server to another Ubuntu/Nginx secured server.
Everything works smoothly on FF, Chrome and Opera. But the 2 other browsers mentioned earlier are apparently identifying the iFrames as third party content.
(I am suddenly thinking about the fact that a wildcard SSL might have solved this issue? I installed two different ones...)