How to build flex resource module in flexmojos4.x

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.