You do need to be running X and some kind of desktop environment or window manager, however. (I installed Xfce but something else should work too.) After that, just aticonfig and restart and install the APP SDK which should detect the GPUs.
You mean that you can remotely (via ssh) launch the mining programs without anybody logged on the console, thus showing only the login window?
I tried but with no luck, can you please give us the details?