Please note: I do not give support to reverse proxy configurations because I think if you need this, you need to modify a page which is not yours. And this is not legal in my opinion. If the http page is yours -> upgrade it to https!
The last option you might have is that you setup a so called reverse proxy (http://en.wikipedia.org/wiki/Reverse_proxy). If you run your own server or your hoster does allow that you use mod_proxy (http://httpd.apache.org/docs/current/mod/mod_proxy.html) AND you have access to the server config you can map the page you want in the iframe to a url of your site. Proxypass is not supported when you can only use a .htaccess file!
There are many tutorials about this topic. In my example below I use Five b from the following page: http://serverfault.com/questions/561892/how-to-handle-relative-urls-correctly-with-a-reverse-proxy.
A more detailed tutorial can be found here: http://www.apachetutor.org/admin/reverseproxies. Details about proxypass and proxypassreverse can be found here http://httpd.apache.org/docs/2.4/mod/mod_proxy.html#proxypass
So a reverse proxy setup can be quite simple but also not working at all depending on the page you want to include. And it does require a lot of time and is really an advanced topic.
As example I show you how I setup a reverse proxy on my localhost for the main page of www.tinywebgallery.com.
1. Enable mod_proxy and mod_substitute in conf/httpd.conf
ProxyPass /twg/ http://www.tinywebgallery.com/ ProxyPassReverse /twg/ http://www.tinywebgallery.com/ AddOutputFilterByType SUBSTITUTE text/html Substitute "s|www.tinywebgallery.com/|localhost/twg/|i"
to the Apache config (conf/httpd.conf or e.g. extra/httpd-proxy.conf).
3. Restart the server
www.tinywebgallery.com is now available at http://localhost/twg/ ;).
And now you would be able to use all features of Advanced iFrame Pro!