facebook comments in ultimate FB plugin

Hi great WPMU team members,

I am just starting to set up the Ultimate Facebook plugin, and I needed to enter the "my_action_name" in the 'use a custom hook' field for the FB comments did not show up.
So I did and all went well, but only thing I see, is I have a responsive website, and the FB comments frame is not. (There is only one width to determine) How can I make the FB comments frame width to adapt on the screen size?

Looking forward to your reply!