Dahdi question

I recently upgraded to asterisk 1.6 with dahdi. I am confused, if I create an extension in freepbx using a dahdi channel it works fine, but when calling out I was getting a weird caller id. So after further investigation I see there is a dahdi-channels.conf file that has all the extension info in it for dahdi channels? When I create an extension in freepbx is updates extensions.conf, but then I also have to update dahdi-channels.conf to match? I guess I am confused.