[Ron]

I haven't configured Trixbox yet, but here is what I use with Asterisk:

[voxalot-in]
username=xxxxxx              ;VoXaLot number goes here
type=peer
secret=xxxxxxxx              ;VoXaLot password goes here
nat=yes
insecure=very
host=voxalot.com
fromuser=xxxxxx              ;VoXaLot number goes here
fromdomain=voxalot.com
context=from-trunk
canreinvite=no

[voxalot-out]
username=xxxxxx              ;VoXaLot number goes here
type=peer
secret=xxxxxxxx              ;VoXaLot password goes here
nat=yes
insecure=very
host=voxalot.com
fromuser=xxxxxx              ;VoXaLot number goes here
fromdomain=voxalot.com
canreinvite=no

Ron