Maven - Include dependent libs in jar without unpacking dependencies?

We're trying to build a client jar that includes unpacked dependent jar's. And the manifest should have class-path entries to the dependent jars. The snippet below works but the jars are unpacked - how can we stop the jars from being unpacked?

       <plugin>
            <artifactId>maven-assembly-plugin</artifactId>

            <configuration>
                <descriptorRefs>
                    <descriptorRef>jar-with-dependencies</descriptorRef>
                </descriptorRefs>

                <archive>
                  <manifest>
                    <addClasspath>true</addClasspath>
                  </manifest>
                </archive>
            </configuration>

            <executions>
                <execution>
                    <id>make-assembly</id>
                    <phase>package</phase>
                    <goals>
                        <goal>single</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>

Indeed, assembling using jar-with-dependencies causes maven to unpack all the dependencies as ${assembly.dependencySets.dependency.unpack} is set to true in the corresponding assembly descriptor.

A simple fix would be to provide an assembly descriptor similar to the jar-with-dependencies.xml and modify ${assembly.dependencySets.dependency.unpack} to false, like this:

EDIT: For an unknown reason, the behavior when using <unpack>false</unpack> is not exactly the same and it seems necessary to add <outputDirectory>/</outputDirectory> to the fileSet or you don't get the expected result.

<assembly>
  <id>uberjar</id>
  <formats>
    <format>jar</format>
  </formats>
  <includeBaseDirectory>false</includeBaseDirectory>
  <dependencySets>
    <dependencySet>
      <unpack>false</unpack>
      <scope>runtime</scope>
    </dependencySet>
  </dependencySets>
  <fileSets>
    <fileSet>
      <directory>${project.build.outputDirectory}</directory>
      <outputDirectory>/</outputDirectory>
    </fileSet>
  </fileSets>
</assembly>