TrixBox Asterisk/FreePBX: Connecting two servers - SIP

[southbeach]

I have two servers:
(1) 192.168.10.90 Minnesota
(2) 192.168.12.90 Miami

I have manually added:

[magno_mia]
deny=all
allow=alaw
type=friend
host=192.168.10.90
qualify=yes
context=from-internal

to server (1) and:

[magno_msp]
deny=all
allow=g729&alaw
type=friend
host=192.168.12.90
qualify=yes
context=from-internal

to server (2). These were typed in /etc/asterisk/sip_general_custom.conf file in both servers respectively.

I then rebooted the servers but, when I dial one of the extension in MSP from MIA, I get the message "All Circuits are buzzy".

Oh, MIA uses extensions 400 - 499 (17 active lines) and MSP uses 500 - 599 (13 active lines). Each server has an outbound route with dial patterns set to 4XX and 5XX respectively.

What am I missing? What else am I to do beside the entries in /etc/asterisk/sip_general_custom.conf and the outbound routes?

Thank you all in advance for your help!