Domain Forwarding Problem

For some of my sites I use more then one Domain, forwarding to a master domain. If I use frame forwarding (the browser shows the domain from which it comes), then on mobile devices the responsive theme settings don’t work. Using the standard forwarding (the browser show the master domain name), then it works.

Example: >frame forwarding > = browser shows: (responsive settings don’t work) >standard forwarding > = browser shows: (everything works fine)

I tested this with different responsive themes (include Foundation), but it’s always the same. At the moment I use the frame forwarding, the theme or RW don’t know that the site is used at a mobile device and use the desktop settings for the display.

Any idea to fix that?