Shade ha sissue generating a source jar on linux, and generates an error on Java 7

We are having issues with the shade plugin on Ubuntu, when it works well on mac OSX. Here is how to reproduce the error:

1) svn co http://svn.apache.org/repos/asf/directory/apacheds/trunk-with-dependencies/
2) cd shared
3) mvn clean install -Dmaven.test.skip

On Mac OSX, maven 3.0.3, Java 1.6.0_29, the shared/all/target directory contains :
rw-rr- 1 elecharny staff 8573 Jan 27 16:20 original-shared-all-1.0.0-M10-SNAPSHOT.jar
rw-rr- 1 elecharny staff 2535518 Jan 27 16:21 shared-all-1.0.0-M10-SNAPSHOT-sources.jar
rw-rr- 1 elecharny staff 2643029 Jan 27 16:20 shared-all-1.0.0-M10-SNAPSHOT.jar

All is fine, the shared-all-1.0.0-M10-SNAPSHOT-sources.jar file contains everything we need.

On Ubuntu 11.10, maven 3.0.3, Java 1.6.0_29, running the exact same command, the shared-all-1.0.0-M10-SNAPSHOT-sources.jar contains 0 bytes.

Same but using Java 7 on ubuntu, we now get an error :
Failed to execute goal org.apache.geronimo.genesis.plugins:tools-maven-plugin:1.4:verify-legal-files (verify-legal-files) on project shared-all: Atifact does not contain any legal files: shared-all-1.0.0-M10-SNAPSHOT-sources.jar

We run the following command on Mac OSX, using maven 3.0.3 and Java 1.6.0_29