Corion,

I use the same firefox binary for X11 and Xvfb. I start it up over ssh (ssh -tXY server firefox) and it runs on the X11 server on my mac. When I run it in Xvfb on the Debian server I can send firefox xdotool key sequences and it works fine (ctrl+l, ctrl+q, etc.). The only difference when I run firefox in Xvfb is I set the DISPLAY variable.