Country code

Good day!
Download and install:
x64
Stable-4.211.64-5
Release Date-07-31-13
FreePBX 2.11, Centos 6.4
Asterisk 11

Add sip trunk, add extensions, add inbound route (trunk -> 101 extension).

How to make that incoming calls are given a country code?

now: 923XXXXXXX
must: 8923XXXXXXX or +7923XXXXXXX

country: Russia federation

Preferably through WEBinterface