Custom manifes entries produce a SecurityException

Given the following configuration:

<profile>
<id>pack2</id>
<build>
<defaultGoal>package</defaultGoal>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<shadedArtifactAttached>true</shadedArtifactAttached>
<shadedClassifierName>jackofall</shadedClassifierName> <!-- Any name that makes sense -->
<transformers>
<transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/>
<transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
<manifestEntries>
<Main-Class>org.ow2.frascati.factory.ManifestLauncher</Main-Class>
<mainComposite>pomodoro</mainComposite>
</manifestEntries>
</transformer>
</transformers>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</profile>

Once the jar is executed, I get this stacktrace:

Exception in thread "main" java.lang.SecurityException: Invalid signature file digest for Manifest main attributes
at sun.security.util.SignatureFileVerifier.processImpl(SignatureFileVerifier.java:221)
at sun.security.util.SignatureFileVerifier.process(SignatureFileVerifier.java:176)
at java.util.jar.JarVerifier.processEntry(JarVerifier.java:277)
at java.util.jar.JarVerifier.update(JarVerifier.java:188)
at java.util.jar.JarFile.initializeVerifier(JarFile.java:321)
at java.util.jar.JarFile.getInputStream(JarFile.java:386)
at sun.misc.URLClassPath$JarLoader$2.getInputStream(URLClassPath.java:689)
at sun.misc.Resource.cachedInputStream(Resource.java:59)
at sun.misc.Resource.getByteBuffer(Resource.java:154)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:249)
at java.net.URLClassLoader.access$000(URLClassLoader.java:56)
at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:319)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:330)
at java.lang.ClassLoader.loadClass(ClassLoader.java:254)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:402)

Maybe this is due to the fact that the custom manifest entry (mainComposite) is written in the middle of the manifest's main entries:

Manifest-Version: 1.0
Build-Jdk: 1.6.0_13
Built-By: veleno
mainComposite: pomodoro <<<<<<
Created-By: Apache Maven
Main-Class: org.ow2.frascati.factory.ManifestLauncher
Archiver-Version: Plexus Archiver