You should be able to use environment variables in your file path. I find that Environment.SpecialFolder.ApplicationDataequivalent %APPDATA%.
, _: % APPDATA%\MyApplication\Logs\trace.log
, .
:
<add fileName="%APPDATA%\MyApplication\Logs\trace.log" header=""
footer="" formatter="Text Formatter"
listenerDataType="Microsoft.Practices.EnterpriseLibrary.Logging.Configuration.FlatFileTraceListenerData, Microsoft.Practices.EnterpriseLibrary.Logging, Version=4.1.0.0, Culture=neutral, PublicKeyToken=null"
traceOutputOptions="None" filter="All" type="Microsoft.Practices.EnterpriseLibrary.Logging.TraceListeners.FlatFileTraceListener, Microsoft.Practices.EnterpriseLibrary.Logging, Version=4.1.0.0, Culture=neutral, PublicKeyToken=null"
name="Flat File Destination" />