Bon le POM au format XML ne passe pas du tout :):)
Nouvel essai
<build>
<plugins>
<plugin>
<groupId>com.pyx4me</groupId>
<artifactId>proguard-maven-plugin</artifactId>
<executions>
<execution>
<phase>package</phase>
<goals><goal>proguard</goal></goals>
</execution>
</executions>
<configuration>
<obfuscate>true</obfuscate>
<injar>${project.build.finalName}.jar</injar>
<outjar>${project.build.finalName}-obfuscate.jar</outjar>
<outputDirectory>${project.build.directory}</outputDirectory>
<proguardInclude>${basedir}/proguard.conf</proguardInclude>
<libs>
<lib>${java.home}/lib/rt.jar</lib>
<lib>${java.home}/lib/jsse.jar</lib>
</libs>
</configuration>
</plugin>
</plugins>
</build>