public ProcessingNode buildNode(Configuration config) throws Exception 
{
        String type = this.treeBuilder.getTypeForStatement(config, Serializer.ROLE + "Selector");
        SitemapLanguage sitemapBuilder = (SitemapLanguage)this.treeBuilder;
        this.views = sitemapBuilder.getViewsForStatement(Serializer.ROLE, type, config);
        this.pipelineHints = sitemapBuilder.getHintsForStatement(Serializer.ROLE, type, config);
        this.node = new SerializeNode(
            type,
            VariableResolverFactory.getResolver(config.getAttribute("src", null), this.manager),
            VariableResolverFactory.getResolver(config.getAttribute("mime-type", null), this.manager),
            VariableResolverFactory.getResolver(config.getAttribute("status-code", null), this.manager)
        );
        this.node.setPipelineHints(this.pipelineHints);
        return this.treeBuilder.setupNode(node, config);
}

 protected boolean hasParameters() 
{
        return true;
}

Serializers can have parameters -- return true

 public  void linkNode() throws Exception 
{
        this.node.setViews(
            ((SitemapLanguage)this.treeBuilder).getViewNodes(this.views)
        );
}