Pablo, I use my fogs as DRLs and they use switched-on power, so they go on and off with the ignition, or the switch independent of the headlights. I used this thread:
http://forums.pelicanparts.com/porsche-911-technical-forum/382588-running-fog-lights-only.html
Since Search sucks on this forum, I use the Google main page and select Settings, then Advanced Search, then use the key word search boxes and then copy the Pelican 911 Tech Forum URL into the Site or Domain field and hit search. You can find virtually anything on this or other sites using this method.