Extension another PBX

long sought, but could not find an answer.
Install:
Asterisk 11.13.0
FreePBX 2.11
Configured IVR
SIP trunk

Task:
In another office is AVAYA PBX.
Need to “cross” address book - That is, the user is connected to Asterisk by typing the extension user with AVAYA he could get through, through “the city”.

On AVAYA extension 501-539.
On ASTERISK - 540-579

Now done so - created SIP Extension (501-539)in the dial indicated local/84951234567@from-internal

How to make automatic redialing extension? Or correctly to solve this problem???

Dial - local/84951234567D(505)@from-internal
dont work.