Problem when setting default values for archetype-metadata.xml

I have an archetype-metadata.xml like this :
<archetype-descriptor name="archetype-jpa">
<fileSets>
...
<fileSets>
<requiredProperties>
<requiredProperty key="groupId">
<defaultValue>com.dexia.sofaxis</defaultValue>
</requiredProperty>
< requiredProperty key="version">
<defaultValue>1.0.0-SNAPSHOT</defaultValue>
</requiredProperty>
</requiredProperties>
</archetype-descriptor>

If I try to use this archetype, groupId and version are not asked on command line, but I then get the exception. If I remove the requiredProperty elements, I don't get it.

[ERROR] The archetype is not configured
org.apache.maven.archetype.exception.ArchetypeNotConfigured: The archetype is not configured
at org.apache.maven.archetype.generator.DefaultFilesetArchetypeGenerator.generateArchetype(DefaultFilesetArchetypeGenerator.java:98)
at org.apache.maven.archetype.generator.DefaultArchetypeGenerator.processFileSetArchetype(DefaultArchetypeGenerator.java:215)
at org.apache.maven.archetype.generator.DefaultArchetypeGenerator.generateArchetype(DefaultArchetypeGenerator.java:130)
at org.apache.maven.archetype.generator.DefaultArchetypeGenerator.generateArchetype(DefaultArchetypeGenerator.java:290)
at org.apache.maven.archetype.DefaultArchetype.generateProjectFromArchetype(DefaultArchetype.java:75)
at org.apache.maven.archetype.mojos.CreateProjectFromArchetypeMojo.execute(CreateProjectFromArchetypeMojo.java:169)
at org.apache.maven.plugin.DefaultPluginManager.executeMojo(DefaultPluginManager.java:447)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:539)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeStandaloneGoal(DefaultLifecycleExecutor.java:493)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoal(DefaultLifecycleExecutor.java:463)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalAndHandleFailures(DefaultLifecycleExecutor.java:311)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeTaskSegments(DefaultLifecycleExecutor.java:224)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:143)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:333)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:126)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:282)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.codehaus.classworlds.Launcher.launchEnhanced(Launcher.java:315)
at org.codehaus.classworlds.Launcher.launch(Launcher.java:255)
at org.codehaus.classworlds.Launcher.mainWithExitCode(Launcher.java:430)
at org.codehaus.classworlds.Launcher.main(Launcher.java:375)