i18n using UiBinder - gwt-maven-plugin

pom.xml

<plugin>  
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>gwt-maven-plugin</artifactId>
    <version>${gwt.version}</version>
    <configuration>
        <!-- your other configuration options -->
        <extraParam>true</extraParam>
        <extra>extras</extra>
    </configuration>
    <executions>
        <execution>
            <phase>prepare-package</phase>
            <goals>
                <goal>compile</goal>
            </goals>
        </execution>
    </executions>
</plugin>