To use the Flex Maven Reports in your application you need to add this plugin repository in your pom.xml :
<pluginRepository>
<id>flex-mvn-report-repository</id>
<url>http://flex-mvn-report.sourceforge.net</url>
<releases>
<enabled>false</enabled>
</releases>
<snapshots>
<enabled>true</enabled>
</snapshots>
</pluginRepository>