Empty voicemail messages

I receive pstn-calls through a SIP-proxy (digisip). If the caller hangs-up before the call is answered the call is dissconnected immediately. However, if the voicemail picks up the call - and the caller hangs-up during the welcome message - there will always be an empty message in my VM-box.

I tried using the minmessage parameter (3-5) in voicemail.conf with no luck.

My answering sequence in extensions.conf:

exten => ${DIGISIPEXTEN},1,Dial(${PHONE1},15,tr)
exten => ${DIGISIPEXTEN},2,Voicemail(u${PHONE1VM})
exten => ${DIGISIPEXTEN},3,Hangup
exten => ${DIGISIPEXTEN},102,Voicemail(b${PHONE1VM})
exten => ${DIGISIPEXTEN},103,Hangup

Thanks for any help,
Jan Eriksson

I was wrong in my first post. I tried changing the minmessage parameter from 0-4. It seems like when I hangup during the welcome message the recorded message is 4s long. This is constant so a recorded message will be (duration + 4s). When I set minmessage to 5 it seems to work.

edit: typo