I have been using an older version of trixbox for a year or so and I use the Device and user mode by setting
AMPEXTENSIONS=deviceanduser
This allows me to have multiple phones in my house and each user can have a line on each phone that all ring simultaneously. I just built a new machine (using the nerdvittles pbx in a flash iso) and after setting deviceanduser mode it appears that no entries are entered into any of the sip_*.conf files and as such my phones cannot connect to the server.
deviceanduser mode should still be working fine (and if you try out svn/trunk which is 2.4 that will be going beta soon, it works even better). What you describe sounds like some sort of bug is keeping the config files from being generated. Try running retrieve_conf from the command line as user asterisk and watch the message to see if it gives you and clues as to what is the problem (assuming the System Status dashboard doesn’t show any problem in the notification panel).
Philippe Lindheimer - FreePBX Project Lead
http//freepbx.org - IRC #freepbx