I've asked on codeplex EntLib forum
Now I am able to make configuration like the following
<loggingConfiguration name="Logging Application Block" tracingEnabled="true">
<categorySources>
<add switchValue="All" name="MyApp">
<listeners>
<add name="EventLog Listener" />
<add name="EMailErrors TraceListener" />
</listeners>
</add>
</categorySources>
<listeners>
<add name="EMailErrors TraceListener" filter="Error"
type="Microsoft.Practices.EnterpriseLibrary.Logging.TraceListeners.EmailTraceListener, Microsoft.Practices.EnterpriseLibrary.Logging, Version=3.1.0.0, Culture=neutral, PublicKeyToken=null"
toAddress="
to@example.com"
fromAddress="
from@example.com"
subjectLineStarter="
test end"
subjectLineEnder="
test start"
smtpServer="
127.0.0.1"
smtpPort="
25"
formatter="
Simple Text Formatter "
listenerDataType="
Microsoft.Practices.EnterpriseLibrary.Logging.Configuration. EmailTraceListenerData, Microsoft.Practices.EnterpriseLibrary.Logging, Version=3.1.0.0, Culture=neutral, PublicKeyToken=null"
traceOutputOptions="
None"
/>
</add>
</listeners>
</loggingConfiguration>
Do NOT confuse listeners/add filter property (local for a listener) with logFilters section(global for the LAB).