diff --git a/jnlp/plugin.jelly b/jnlp/plugin.jelly
index d5c0edcb..89de0cb0 100644
--- a/jnlp/plugin.jelly
+++ b/jnlp/plugin.jelly
@@ -161,6 +161,16 @@
                         <j:if test="${dep.getProperty('jnlp.native.jar')=='true'}">
                             <nativelib href="${lib.file.name}"/>
                         </j:if>
+                        <j:if test="${dep.getProperty('jnlp.extension.jnlp')!= null}">
+                            <j:choose>
+                                <j:when test="${dep.getProperty('jnlp.extension.site')!= null})">
+                                    <extension name="${lib.file.name}" href="http://${dep.getProperty('jnlp.extension.site')}/${dep.getProperty('jnlp.extension.dir')}/${dep.getProperty('jnlp.extension.jnlp')}"/>
+                                </j:when>
+                                <j:otherwise>
+                                    <extension name="${lib.file.name}" href="${dep.getProperty('jnlp.extension.dir')}/${dep.getProperty('jnlp.extension.jnlp')}"/>
+                                </j:otherwise>
+                            </j:choose>
+                        </j:if>
                     </j:forEach>
                     <j:set var="depVer" value="${pom.currentVersion}"/>
                     <j:if test="${context.getVariable('maven.jnlp.cert.version') != null}">
diff --git a/jnlp/project.xml b/jnlp/project.xml
index d2b117c5..85f87f81 100644
--- a/jnlp/project.xml
+++ b/jnlp/project.xml
@@ -53,6 +53,14 @@
       </roles>
     </developer>
   </developers>
+  <contributors>
+    <contributor>
+      <name>Martin Skopp</name>
+      <email>skopp@riege.de</email>
+      <organization>Riege Software International</organization>
+      <timezone>+1</timezone>
+    </contributor>
+  </contributors>
   <dependencies/>
   <versions>
     <version>
diff --git a/jnlp/xdocs/changes.xml b/jnlp/xdocs/changes.xml
index 424c6def..2504cd6f 100644
--- a/jnlp/xdocs/changes.xml
+++ b/jnlp/xdocs/changes.xml
@@ -26,6 +26,7 @@
   </properties>
   <body>
     <release version="1.4.1-SNAPSHOT" date="in CVS">
+      <action dev="evenisse" type="add" issue="MPJNLP-2">Add extension support.</action>
       <action dev="dion" type="fix" issue="MPJNLP-13">Fix bad signed jar name</action>
     </release>
     <release version="1.4" date="2004-07-12">
diff --git a/jnlp/xdocs/properties.xml b/jnlp/xdocs/properties.xml
index 3ba6b37a..76276385 100644
--- a/jnlp/xdocs/properties.xml
+++ b/jnlp/xdocs/properties.xml
@@ -312,7 +312,7 @@
     </section>
     <section name="Keystore settings">
       <table>
-        <tr><th>Property</th><th>Description</th><th>See</th></tr>
+        <tr><th>Property</th><th>Optional?</th><th>Description</th><th>Default</th></tr>
         <tr>
           <td>maven.jnlp.signjar.store</td>
           <td>Yes</td>
@@ -439,6 +439,40 @@
       </properties>
     </dependency>
   ]]></source>
+
+      <p>
+      Or for using JNLP extension mechanism :
+      </p>
+
+  <source><![CDATA[
+    <dependency>
+      <id>jarid</id>
+      <version>jarversion</version>
+      <properties>
+        <jnlp.extension.site>hostname</jnlp.extension.site>
+        <jnlp.extension.dir>directory</jnlp.extension.dir>
+        <jnlp.extension.jnlp>jnlp-filename</jnlp.extension.jnlp>
+      </properties>
+    </dependency>
+  ]]></source>
+
+      <p>
+      The JNLP extension mechanism is useful e.g. as a workaround when
+      JAR files signed by different certificates are used, see
+      <a href="http://java.sun.com/products/javawebstart/faq.html#72">Java Webstart FAQ, How do I use JAR files that are signed by different certificates?)</a>.
+      </p>
+      <p>
+      When using JNLP extension feature, <tt>jnlp.extension.site</tt>
+      must not contain URL prefix - "http://" is the only protocol
+      supported now.
+      Property <tt>jnlp.extension.site</tt> is a optional, if omited
+      a relative URL is constructed from <tt>jnlp.extension.dir</tt>
+      and <tt>jnlp.extension.jnlp</tt>.  If JNLP file is stored in
+      the same directory as the generated JNLP file and one likes
+      to avoid absolute pathnames, one should use "." as value for
+      <tt>jnlp.extension.dir</tt>.
+      </p>
+
     </section>
     <section name="How to define the main jar?">
       <p>