I had trouble getting the gc100 recognized. Some troubleshooting led me to find that there was a bug in the gc100 install script that came with LMCE 1.1-b2, so that it would not detect the MAC address of the gc100. So I have made some dirty hacks to hardcode the MAC address, you can find the info in the post here:
http://smart-home-blog.com/archives/688 (comments section)
I should file a mantis for this, but I don't know if I am the only one with that same prob.
Thank you so much for that hint, I think it's pretty safe to say that the gc100 support is definately broken. And since it's a perl script (/usr/pluto/bin/gc100-conf.pl), I have no way of fixing it properly. So I just went with the hardcoded-mac hack, now it works. I also found the logfile for this script, just in case anyone else is interested in trouble shooting:
/var/log/pluto/gc100-conf.log