Trouble dial forreign countries from Lync with SIP trunk

I have noticed some trouble due to timeout when calling abroad.
What I have done that fixed this problem was:

Configuring Parameters
Some of the above timeouts can be configured. The file which has the configurable parameters is 'OutboundRouting.exe.config”  Use caution when changing these values, as a rule of thumb try not to increase or decrease the value by more than 25% of its original value.

from OutboundRouting.exe.config
<configuration>
    <appSettings>
      <add key="FailOverTimeout" value="10000"/>
      <add key="MinGwWaitingTime" value="1"/>
      <add key="MaxGwWaitingTime" value="20"/>
      <add key="FailuresForGatewayDown" value="10"/>
      <add key="FailuresForGatewayLessPreferred" value="25"/>
      <!-- Valid values are between 5 and 600 -->
      <add key="HealthMonitoringInterval" value="300"/>
      <!-- Valid values are between 60 and 3600 -->
      <add key="GatewayStateReportingInterval" value="1800" />
  </appSettings>
</configuration>

The FailOverTimeout should be increased to the desired time limit.
The file is found under C:\Program Files\Microsoft Lync Server 2010\Server\Core

Change this from 10000 to 20000 (20 sec). Save the file and reboot the frontend server.
<add key="FailOverTimeout" value="20000"/>