Creating Custom UI Compositions

See Creating Custom EL Functions as a starting point

Create another xml called META-INF/compositions.taglib.xml

<?xml version="1.0"?>
<!DOCTYPE facelet-taglib PUBLIC
"-//Sun Microsystems, Inc.//DTD Facelet Taglib 1.0//EN"
"facelet-taglib_1_0.dtd">
<facelet-taglib>
    <namespace>http://enhancements.seam/jsf</namespace>
    <tag>
        <tag-name>print</tag-name>
        <source>../layout/enhancements/print.xhtml</source>
    </tag>
</facelet-taglib>

Add that to your web.xml

<context-param>
    <param-name>facelets.LIBRARIES</param-name>
    <param-value>
        /META-INF/elfunctions.taglib.xml; compositions.taglib.xml
    </param-value>
</context-param>

Create the print.xhtml in WebContent/layout/enhancements/print.xhtml (JBDS) or view/layout/enhancements/print.xhtml (seam-gen) :

<ui:composition  xmlns="http://www.w3.org/1999/xhtml"
		 xmlns:ui="http://java.sun.com/jsf/facelets"
		 xmlns:h="http://java.sun.com/jsf/html"
		 xmlns:f="http://java.sun.com/jsf/core"
		 xmlns:s="http://jboss.com/products/seam/taglib"
		 xmlns:rich="http://richfaces.org/rich"
		 xmlns:a="http://richfaces.org/a4j"
		 xmlns:e="http://org.el.func/SeamFunc"
		 xmlns:c="http://java.sun.com/jstl/core">
    
    <h:outputText value="#{e:concat('Hello ', message)}" />
	 
</ui:composition>

Now in your view or WebContent/ folder create test.xhtml

<!DOCTYPE composition PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<ui:composition xmlns="http://www.w3.org/1999/xhtml"
		xmlns:s="http://jboss.com/products/seam/taglib"
		xmlns:ui="http://java.sun.com/jsf/facelets"
		xmlns:f="http://java.sun.com/jsf/core"
		xmlns:h="http://java.sun.com/jsf/html"
		xmlns:rich="http://richfaces.org/rich"
		xmlns:a="http://richfaces.org/a4j"
		xmlns:e="http://org.el.func/SeamFunc"
		xmlns:custom="http://enhancements.seam/jsf"
		template="/layout/template.xhtml">
		
    <ui:define name="body">
	
	<custom:print message="World" />
		
    </ui:define>
    
</ui:composition>