maven-assembly doesn't support war format

Trying to use the assembly plugin to repackage a war, I got the exception below. The functionality was needed to implemented multi-webstart application deployment in relation to the Webstart Plugin [1]

It fails miserably because of the missing webxml attribute required by the WebArchiver, triggered because the specified format is war.

I was told on #maven that the assembly is not meant to package war. I don't see why it couldn't So I mailed on @users [2]. Someone also asked for similar funcionality [3].
So repackaging a war is clearly an required functionality.

Should we consider the assembly plugin one way to implement this feature, and this is issue is indeed real?
Or should I take another approach, like move the assembly plugin execution as part of an earlier phase (e.g. process-resources) inside the war project ?

Some links

Links:
[1] http://docs.codehaus.org/display/MOJO/Webstart+Plugin
[2] http://thread.gmane.org/gmane.comp.jakarta.turbine.maven.user/29177
[3] http://thread.gmane.org/gmane.comp.jakarta.turbine.maven.user/29243

Here's my assmbly descriptor:

<assembly>
<id>main</id>
<formats>
<format>war</format>
</formats>
<includeBaseDirectory>false</includeBaseDirectory>
<dependencySets>
<dependencySet>
<outputDirectory>/</outputDirectory>
<includes>
<include>myproject:webapp</include>
</includes>
<unpack>true</unpack>
<scope>runtime</scope>
</dependencySet>
<dependencySet>
<outputDirectory>webstart</outputDirectory>
<includes>
<include>myproject:webstart1</include>
</includes>
<unpack>true</unpack>
<scope>runtime</scope>
</dependencySet>
</dependencySets>
</assembly>

and here's a part of the pom

<dependencies>

<dependency>
<groupId>myproject</groupId>
<artifactId>webapp</artifactId>
<version>$

</version>
<type>zip</type>
</dependency>

Here's the log:

[DEBUG] – end configuration –
[INFO] [assembly:assembly]
[...]
[INFO] ----------------------------------------------------------------------------
[ERROR] BUILD ERROR
[INFO] ----------------------------------------------------------------------------
[INFO] Error creating assembly: webxml attribute is required

[INFO] ----------------------------------------------------------------------------
[DEBUG] Trace
org.apache.maven.lifecycle.LifecycleExecutionException: Error creating
assembly: webxml attribute is required
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:544)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeStandaloneGoal(DefaultLifecycleExecutor.java:482)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoal(DefaultLifecycleExecutor.java:452)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalAndHandleFailures(DefaultLifecycleExecutor.java:301)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeTaskSegments(DefaultLifecycleExecutor.java:214)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:137)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:316)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:113)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:249)
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)
Caused by: org.apache.maven.plugin.MojoExecutionException: Error
creating assembly: webxml attribute is required
at org.apache.maven.plugin.assembly.AssemblyMojo.execute(AssemblyMojo.java:173)
at org.apache.maven.plugin.DefaultPluginManager.executeMojo(DefaultPluginManager.java:399)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:519)
... 16 more
Caused by: org.codehaus.plexus.archiver.ArchiverException: webxml
attribute is required
at org.codehaus.plexus.archiver.war.WarArchiver.initZipOutputStream(WarArchiver.java:139)
at org.codehaus.plexus.archiver.zip.AbstractZipArchiver.createArchiveMain(AbstractZipArchiver.java:327)
at org.codehaus.plexus.archiver.zip.AbstractZipArchiver.createArchive(AbstractZipArchiver.java:229)
at org.apache.maven.plugin.assembly.AssemblyMojo.createArchive(AssemblyMojo.java:215)
at org.apache.maven.plugin.assembly.AssemblyMojo.execute(AssemblyMojo.java:165)
... 18 more
[INFO] ----------------------------------------------------------------------------
[INFO] Total time: 7 seconds
[INFO] Finished at: Fri Oct 21 12:44:25 CEST 2005
[INFO] Final Memory: 3M/7M
[INFO] --------------------------------------------