I am struggling with the same problem. Maybe the package.html file should go into src/main/javadoc/package.html but I could not make this work either. I tried to specify it under sources, resources, and siteResources. It simply does not end up in the packaged archetype jar.

I've copied the quickstart archetype to the Maven sandbox and added package.html, overview.html and App.properties to demonstrate problems with non-Java resources: http://svn.apache.org/repos/asf/maven/sandbox/trunk/archetype/maven-archetype-quickstart/

The readme file there explains the problems I'm having, including the inability to get package.html into the archetype jar.

The package.html file is being excluded by maven-jar-plugin.

http://maven.apache.org/plugins/maven-jar-plugin/xref/org/apache/maven/plugin/jar/AbstractJarMojo.html

39 private static final String[] DEFAULT_EXCLUDES = new String[]{"**/package.html"};
...
152 archiver.getArchiver().addDirectory( contentDirectory, DEFAULT_INCLUDES, DEFAULT_EXCLUDES );

It does not appear to be configurable.

Changing the summary to be more specific, since only package.html is a problem.

Other non-Java resources (such as overview.html) do get included in the archetype jar.

This issue will be fixed by NG-alpha-1

With the patch for MJAR-30 there is now a workaround:
Configure the jar plugin with a dummy exclude to override the default
<configuration>
<excludes>
<exclude>some-file-that-does-not-exist</exclude>
</excludes>
</configuration>

These issues are addressed since the 2.0-alpha-n version of the plugin