Default terminal in GNOME 3

I wondered how to set the default terminal in GNOME 3. The internet revealed

gsettings set org.gnome.desktop.default-applications.terminal exec <terminal> gsettings set org.gnome.desktop.default-applications.terminal exec-arg "'-e'"

This raises 2 questions: 1. Will it be possible to set the default terminal again in GNOME 3.2? 2. Where is 'exec-arg' arg coming from? In the past we had the xml files in /usr/share/gnome-control-center/default-apps/ which contained an 'exec-flag'. How can I as a maintainer of several terminal applications let people know the proper exec-flag/exec-arg?

Regards, Christoph