Manifest Entries in execution elements are completely ignored

When multiple executions are used, (for example when deploying a test-jar as well) execution specific Manifest entries are not used. Only "Global" configurations are used.

<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.4</version>
<configuration>
<archive>
<manifest>
<addDefaultImplementationEntries>true</addDefaultImplementationEntries>
</manifest>
<manifestEntries>
<!-- These entries are specific to deployable jar only. -->
<!--
<Premain-Class>com.demo.vm.plugins.Agent</Premain-Class>
<Agent-Class>com.demo.vm.plugins.Agent</Agent-Class>
<Boot-Class-Path>asm-4.0.jar</Boot-Class-Path>
-->
</manifestEntries>
</archive>
</configuration>
<executions>
<execution>
<id>vm</id>
<configuration>
<!-- This set of entries are ignored -->
<archive>
<manifest>
<addClasspath>true</addClasspath>
<!-- <addDefaultImplementationEntries>true</addDefaultImplementationEntries>
<classpathPrefix>Boot-</classpathPrefix> -->
</manifest>
<manifestEntries>
<Premain-Class>com.demo.vm.plugins.Agent</Premain-Class>
<Agent-Class>com.demo.vm.plugins.Agent</Agent-Class>
<Boot-Class-Path>asm-4.0.jar</Boot-Class-Path>
</manifestEntries>
</archive>
</configuration>
<goals>
<goal>jar</goal>
</goals>
</execution>
<execution>
<id>test</id>
<goals>
<goal>test-jar</goal>
</goals>
</execution>
</executions>
</plugin>
NOTE: Versions after 2.4 do not seem to be available from the main repositories? 2.4 was the latest I was able to download.