I've used l4ndash in the past and it is a good tool.
Have you tried changing this in the web.config?
This should load all files in that folder.
<datasource name="XML Text file" Description="XML Text file (output from FilAppender or RollingFileAppender)">
<provider type="L4NDashXmlTextFileProvider.XmlTextFileProvider" assembly="L4NDashXmlTextFileProvider, Version=2.4, Culture=neutral"/>
<predefinedsearchfilter value="Filters\DefaultSearchFilters.xml"/>
<providersettings>
<filename value="C:\MyApp\Logs\*.*" />
<SleepOnRename value="100"/>
</providersettings>