TDM400 dialout problem for billing

Helo,
The problem is that all outgoing calls results always answered even if the number called is busy or not responding.
In this way you will not be able to do billin on analog lines. Is this possible?

I use: Asterisk 1.4.21-2 - FreePBX 2.5 - TDM400P (in Italy)

Show Asterisk CLI to outgoing call on zap channel 1.

[KPBXCLI> – Executing [s@macro-dialout-trunk:18][1;36;40mGotoIf[0;37;40m("[1;35;40mSIP/102-b7ca6930[0;37;40m","[1;35;40m0?customtrunk[0;37;40m") in new stack
[KPBX
CLI> – Executing [s@macro-dialout-trunk:19][1;36;40mDial[0;37;40m("[1;35;40mSIP/102-b7ca6930[0;37;40m","[1;35;40mZAP/1/[NUMBER]|300|twTW[0;37;40m") in new stack
[KPBXCLI> – Called 1/[NUMBER]
[KPBX
CLI> – Zap/1-1 answered SIP/102-b7ca6930
[KPBX*CLI> – Hungup ‘Zap/1-1’

Always answered even if the number called is busy or not responding. In this case, not responding.

Please, help me !

My zaptel.conf e zapata.conf

zaptel.conf
fxsks=1

loadzone = it
defaultzone = it

zapata.conf
[trunkgroups]

[channels]

language=it
context=from-zaptel
signalling=fxs_ks
rxwink=300
usecallerid=yes
hidecallerid=no
callwaiting=no
usecallingpres=yes
callwaitingcallerid=yes
threewaycalling=yes
transfer=yes
cancallforward=yes
callreturn=yes
echocancel=yes
echocancelwhenbridged=yes
echotraining=800
rxgain=4.0
txgain=0.0
group=0
callgroup=1
pickupgroup=1
immediate=no
relaxdtmf=yes
faxdetect=incoming
group=0
channel => 1