lesscss-maven-plugin没有生成源地图？

Question

我目前正在使用org.codehaus.mojo的lesscss-maven-plugin; 构建正常，并且正在正确编译。 我怎么没有生成任何源地图：

在我的pom.xml上：

<plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>lesscss-maven-plugin</artifactId>
    <version>1.0-beta-3</version>
    <configuration>
        <force>true</force>
        <lessJs>${project.basedir}/src/main/resources/lessjs/less.1.7.5-min.js</lessJs>
        <sourceDirectory>${project.build.directory}/${project.build.finalName}/</sourceDirectory>
        <outputDirectory>${project.build.directory}/${project.build.finalName}-LESS</outputDirectory>
        <compress>true</compress>
        <includes>
            <include>r/assets/bootstrap.less</include>
            <include>r/assets/page.less</include>
        </includes>
    </configuration>
    <executions>
        <execution>
            <goals>
                <goal>compile</goal>
            </goals>
            <phase>prepare-package</phase>

        </execution>
    </executions>
</plugin>

在less.js上我在顶部添加了这个：

less: {
    env: "development",
    "development": {
        options: {
            compress: true,
            yuicompress: true,
            optimization: 2,
            sourceMap: true,
            sourceMapFilename: "r/css/styles.map"

        },
        files: {
            "r/css/bootstrap.css": "r/assets/bootstrap.less",
            "r/css/page.css": "r/assets/page.less",
        }
    }
}

我忘记了什么吗？ TIA。