[Asterisk-Users] Remote answer not detected

[DB]

Here's my a section of my simple extensions.conf

exten => s,1,Answer
exten => s,2,playback(thx4call)
exten => s,3,Dial(Zap/1|15) ; Calls  channel 1
exten => s,4,playback(trying_bert)
exten => s,5,Dial(Zap/4/2326932|15)
exten => s,6,Voicemail,u100
exten => s,7,hangup
exten => s,104,Voicemail,b100
exten => s,105,hangup
exten => s,106,Voicemail,u100

It works, but when the call is routed out on ZAP/4 (at priority 5), 
Asterisk seems to not realize the call is answered. After 15 seconds it 
proceeds to voicemail interrupting the call. Can anyone help?

DB