Maven Assembly Create Custom Format

Question

As part of a bigger project, I want to package some items I download together with some jar files as a .tar.gz package. And I did that successfully.

But now I want to "rename" that .tar.gz to something custom (e.a. to mypackage.banana)

Is there an easy way to achieve this?

What I have so far id accomplished using https://github.com/maven-download-plugin/maven-download-plugin

<build>
    <plugins>
        <plugin>
            <groupId>com.googlecode.maven-download-plugin</groupId>
            <artifactId>download-maven-plugin</artifactId>
            <version>1.2.1</version>
            <executions>
                <execution>
                    <phase>generate-resources</phase>
                    <goals>
                        <goal>wget</goal>
                    </goals>
                    <configuration>
                        <url>${some.jar.file.url}</url>
                        <outputDirectory>${project.build.directory}/lib</outputDirectory>
                        <url>${some.models.zip.url}</url>
                        <unpack>true</unpack>
                        <outputDirectory>${project.build.directory}/data</outputDirectory>
                    </configuration>
                </execution>
            </executions>
        </plugin>

        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-assembly-plugin</artifactId>
            <version>2.2-beta-5</version> <!-- Old -->
            <executions>
                <execution>  <!-- Build tar.gz archive. -->
                    <id>tar</id>
                    <phase>package</phase>
                    <goals>
                        <goal>single</goal>
                    </goals>
                    <configuration>
                        <descriptors>
                            <descriptor>src/tar.xml</descriptor>
                        </descriptors>
                        <finalName>project-${project.version}-el6</finalName>
                        <appendAssemblyId>false</appendAssemblyId>
                    </configuration>
                </execution>  <!-- /NewStuff -->
            </executions>
        </plugin>
    </plugins>
</build>

using tar.xml:

<assembly>
<id>tar</id>
<formats>
    <format>tar.gz</format>
</formats>
<fileSets>
    <fileSet>
        <directory>target/data</directory>
        <outputDirectory>/data</outputDirectory>
    </fileSet>
    <fileSet>
        <directory>target/lib</directory>
        <outputDirectory>/lib</outputDirectory>
    </fileSet>
    <fileSet>
        <directory>meta</directory>
        <outputDirectory>/meta</outputDirectory>
    </fileSet>
</fileSets>