Route and Vlan Problem?

Hi,

My configuration to connect my IP provider (2 vlan 1. voice 2. Internet


  192.168.1.0 ---------eth1-------BOX---------eth0.2311 84.16.31.10  
(public IP gw 84.16.31.9)
                                                                         
   eth0.2219 10.150.21.88 (Voip gx 10.150.21.81)



My routes :
     net 10.0.0.0 -> 10.150.21.81 (for voice)
     default -> 84.16.31.9 (for internet)


When I ping www.google.fr it's ok... I have a reply and packet sent  
through 84.16.31.9
When I make a call my asterisk send to sip server 10.43.0.71 through  
10.150.21.81

The problem is :
    - When I make and call, the ping stop.... and restart when I hangup
    - When I ping, udp flow don't pass...

I don't known if it's a kernel problem, a configuration problem...

Thanks in advance,
Jeremy