diff --git a/build.xml b/build.xml
index c404300f5..1d7f2b0aa 100644
--- a/build.xml
+++ b/build.xml
@@ -611,16 +611,18 @@
 
       <manifest>
         <section name="${optional.package}">
+          <attribute name="Extension-name"
+                     value="org.apache.tools.ant.taskdesfs.optional" />
           <attribute name="Specification-Title"
                      value="Apache Ant Optional Tasks" />
           <attribute name="Specification-Version"
-                     value="${version}" />
+                     value="${manifest-version}" />
           <attribute name="Specification-Vendor"
                      value="Apache Software Foundation" />
           <attribute name="Implementation-Title"
                      value="org.apache.tools.ant.taskdefs.optional" />
           <attribute name="Implementation-Version"
-                     value="${version} ${TODAY}" />
+                     value="${manifest-version}" />
           <attribute name="Implementation-Vendor"
                      value="Apache Software Foundation" />
         </section>