Can not change Extension to device and user

I just installed Asterisk 1.8 with FreeBPX 2.10. I’d like to use device and user. I tried to change extensions to device and user (/etc/amportal.conf) AMPEXTENSIONS=deviceanduser, but not see user and device in FreePBX, event changed in FreePBX --> Settings—>Advanced Settings—> User & Devices Mode : [extensions --> deviceanduser]. thanks in advance for your respond.