Weird problem with voice mail and digital receptionist

[eraserpt]

I came accross with a problem, when i configure my voip provider (voipbuster) to foward to a extension it works fine, but if i configure it to foward the call to digital receptionist or voicemail it answer my call but i dont hear nothing! The weird thing about this is if i configure to foward the call to a extension ring for 5 seconds and if nobody answer, to foward to digital receptionist or voicemail it works!

The problem also happens if i foward the call to a entension that isnt registered then forward to DR or voicemail!
It has to ring on a extension for at least 1 second for DR or voicemail to work!

Here is the log:

21:14:06.984 MediaServerReporting::RTPReceiver [MS105000] Call(1) Ln:10000@VoipBuster: No RTP packets were received on 00000001@:remoteAddr=195.219.64.19:11956,extAddr=85.243.112.145:42088,localAddr=0.0.0.0:9000

21:14:06.921 StratInOut:nHangUp [CM104007] Call(1): Call from Ln:10000@VoipBuster to 999 has been terminated by Ln:10000@VoipBuster; cause: BYE; from IP:194.120.0.198

21:13:23.578 CallLegImpl:nConnected [CM103001] Call(1): Created audio channel for Ln:10000@VoipBuster (195.219.64.19:11956) with Media Server (85.243.112.145:42088)

21:13:22.984 CallConf:nIncoming [CM103002] Call(1): Incoming call from PredatorPT (Ln:10000@VoipBuster) to sip:[email protected]:38148

Any ideias?

Thanks