GOautodial Open Source Omni-channel Contact Center Suite

Hello all,
i'm trying to get ringback for 3way-call conference when dialing a 3rd party number (or an internal extension). Goautodial version 2.1ce

This is my extension.conf:

exten => _92.,1,Answer
exten => _92.,2,Dial(${TRUNKloop}/2${EXTEN:2},,tTor)
exten => _92.,3,Hangup

This is my carrier configuration:

Reg String: register => 2001:xxxx@192.168.82.156:5060/2001
Account Entry:
[mypbx2-out]
disallow=all
allow=ulaw
type=friend
username=2001
secret=xxxxx
host=192.168.82.156
dtmfmode=rfc2833
context=trunkinbound
fromuser=2001
insecure=very

Protocol SIP

Global String
MYPBX2OUT = SIP/mypbx2-out

Dialplan entry:
exten => _2.,1,AGI
exten => _2.,2,Dial(SIP/${EXTEN:0}@mypbx2-out,,Ttor)
exten => _2.,3,Hangup

In my campaign the 3-way dial prefix is 92, according to my specs

.............................

Now when i try to call a number with only 3-digits (like an extension on the other side of pbx i.e. 203) i need to insert the 92 prefix (i.e. 92203) and the call is placed thru the IAX proxy. But i never see the right channel in vicidial webphone. In this case NO ringback is heared. When i try to call directly from my x-lite the 92203 the ringback is present.

I've done an outside test call with another number (i.e. 000303030303003). The channel showed in vicidial webphone (in this case) is correct BUT ANYWAY no RINGBACK is heared.

1st Question: How i can put ALWAYS the 3way prefix also with only 3digits number.
2nd Question: what i'm doing wrong?!? No ringback!!!

Thanks in advance for help.
Leonardo.