How to build flex resource module in flexmojos4.x - apache-flex

Question

I use flexmojos plugin to manage my flex app. At first, I use flexmojos3.8, the following is fragment to create seperate resource module. If my app support en_US, zh_Ch, I can get MainApp_en_US.swf and MainApp_zh_CN.swf. In my app, I can load proper resource module according to browser's language.
<plugin>
<groupId>org.sonatype.flexmojos</groupId>
<artifactId>flexmojos-maven-plugin</artifactId>
<dependencies>
<dependency>
<groupId>com.adobe.flex</groupId>
<artifactId>compiler</artifactId>
<version>${flex.sdk.version}</version>
<type>pom</type>
</dependency>
</dependencies>
<configuration>
<sourceFile>MainApp.mxml</sourceFile>
<resourceBundlePath>
src/main/flex/locale/{locale}
</resourceBundlePath>
<runtimeLocales>${locales}</runtimeLocales>
<mergeResourceBundle>false</mergeResourceBundle>
<runtimeLocaleOutputPath>
/{contextRoot}/MainApp_{locale}.{extension}
</runtimeLocaleOutputPath>
<rslUrls>
<url>/{contextRoot}/rsl/{artifactId}.{extension}</url>
</rslUrls>
</configuration>
</plugin>
But when I upgrade flexmojos 4.0-RC2, I find the changes are big. The config changes to
.....
MainApp.mxml
src/main/flex/locale/{locale}
<localesRuntime>
<locale>en_US</locale>
<locale>fr_FR</locale>
<locale>zh_CN</locale>
</localesRuntime>
//Output resource module to current pathe (/target)
<localesOutputPath>
/
</localesOutputPath>
//Define your resource moudle name pattern
<resourceBundleNames>
MainApp_{locale}
</resourceBundleNames>
.....
</configuration>
It works after lots of trying. The last config like above.