diff --git a/proposal/myrmidon/antlib.xml b/proposal/myrmidon/antlib.xml
index 6b70d9fe2..6ff50788b 100644
--- a/proposal/myrmidon/antlib.xml
+++ b/proposal/myrmidon/antlib.xml
@@ -56,24 +56,21 @@ Legal:
       <fileset dir="${java.dir}">
         <include name="${antlib.include}/*.java" />
       </fileset>
-      <template templateFile="${manifest.dir}/core-ant-descriptor.template"
+      <template templateFile="${manifest.dir}/ant-descriptor.template"
                 destinationfile="${antlib.descriptor}"/>
-      <template templateFile="${manifest.dir}/builtin-ant-roles.template"
+      <template templateFile="${manifest.dir}/ant-roles.template"
                 destinationfile="${antlib.role.descriptor}"/>
     </xdoclet>
   </target>
 
   <!-- Creates the jars file -->
   <target name="jar" depends="xdoclet">
-    <jar jarfile="${build.lib}/${antlib.name}.atl" basedir="${build.classes}">
+    <antlib-jar jarfile="${build.lib}/${antlib.name}.atl"
+                basedir="${build.classes}"
+                descriptor="${gen.dir}/${antlib.descriptor}"
+                rolesDescriptor="${gen.dir}/${antlib.role.descriptor}">
       <include name="${antlib.include}" />
-      <zipfileset dir="${gen.dir}" fullpath="META-INF/ant-descriptor.xml">
-        <include name="${antlib.descriptor}"/>
-      </zipfileset>
-      <zipfileset dir="${gen.dir}" fullpath="META-INF/ant-roles.xml">
-        <include name="${antlib.role.descriptor}"/>
-      </zipfileset>
-    </jar>
+    </antlib-jar>
   </target>
 
 </project>
diff --git a/proposal/myrmidon/build.xml b/proposal/myrmidon/build.xml
index 13a2e6ea1..97ed68a8d 100644
--- a/proposal/myrmidon/build.xml
+++ b/proposal/myrmidon/build.xml
@@ -182,6 +182,16 @@ Legal:
 
   </target>
 
+  <!-- Compiles and installs the custom build tasks -->
+  <target name="custom-tasks">
+      <property name="custom-tasks-dir" value="${build.dir}/tasks"/>
+      <mkdir dir="${custom-tasks-dir}"/>
+      <javac srcdir="src/make" destdir="${custom-tasks-dir}">
+      </javac>
+      <taskdef name="antlib-jar" classname="org.apache.myrmidon.build.AntlibJarTask">
+          <classpath location="${custom-tasks-dir}"/>
+      </taskdef>
+  </target>
 
   <!-- Compiles the source code -->
   <target name="compile" depends="check_for_optional_packages">
@@ -292,7 +302,7 @@ Legal:
   </target>
 
   <!-- Creates the jars file -->
-  <target name="jars" depends="compile">
+  <target name="jars" depends="custom-tasks, compile">
 
     <mkdir dir="${build.lib}"/>
 
@@ -302,9 +312,12 @@ Legal:
       <include name="org/apache/myrmidon/launcher/*" />
     </jar>
 
-    <jar jarfile="${build.lib}/myrmidon-api.jar"
-         basedir="${build.classes}"
-         manifest="${manifest.dir}/myrmidon-api.mf">
+    <antlib-jar jarfile="${build.lib}/myrmidon-api.jar"
+                basedir="${build.classes}"
+                manifest="${manifest.dir}/myrmidon-api.mf"
+                rolesDescriptor="${manifest.dir}/builtin-ant-roles.xml"
+                descriptor="${manifest.dir}/builtin-ant-descriptor.xml"
+                servicesDescriptor="${manifest.dir}/core-services.xml" >
       <include name="org/apache/myrmidon/api/*" />
       <include name="org/apache/myrmidon/aspects/*" />
       <include name="org/apache/myrmidon/converter/*" />
@@ -316,19 +329,7 @@ Legal:
 <!--      <include name="org/apache/myrmidon/*" />
       <include name="org/apache/myrmidon/components/**"/>
       <include name="org/apache/myrmidon/frontends/*" /> -->
-
-      <zipfileset dir="${manifest.dir}" fullpath="META-INF/ant-roles.xml">
-        <include name="builtin-ant-roles.xml"/>
-      </zipfileset>
-
-      <zipfileset dir="${manifest.dir}" fullpath="META-INF/ant-descriptor.xml">
-        <include name="builtin-ant-descriptor.xml"/>
-      </zipfileset>
-
-      <zipfileset dir="${manifest.dir}" fullpath="META-INF/ant-services.xml">
-        <include name="core-services.xml"/>
-      </zipfileset>
-    </jar>
+    </antlib-jar>
 
 <!--
     <jar jarfile="${build.lib}/myrmidon-framework.jar"
@@ -391,18 +392,14 @@ Legal:
     </ant>
     -->
 
-    <jar jarfile="${build.lib}/selftest.atl"
+    <antlib-jar jarfile="${build.lib}/selftest.atl"
          basedir="${build.classes}"
-         manifest="${manifest.dir}/selftest.mf">
+         manifest="${manifest.dir}/selftest.mf"
+         descriptor="${manifest.dir}/selftest-ant-descriptor.xml"
+         rolesDescriptor="${manifest.dir}/empty-roles.xml">
       <include name="org/apache/antlib/selftest/**" />
       <exclude name="org/apache/antlib/selftest/extension1/**" />
-      <zipfileset dir="${manifest.dir}" fullpath="META-INF/ant-descriptor.xml">
-        <include name="selftest-ant-descriptor.xml"/>
-      </zipfileset>
-      <zipfileset dir="${manifest.dir}" fullpath="META-INF/ant-roles.xml">
-        <include name="empty-roles.xml"/>
-      </zipfileset>
-    </jar>
+    </antlib-jar>
 
     <jar jarfile="${build.lib}/selftest-extension1.jar"
          basedir="${build.classes}"
diff --git a/proposal/myrmidon/src/make/org/apache/myrmidon/build/AntlibJarTask.java b/proposal/myrmidon/src/make/org/apache/myrmidon/build/AntlibJarTask.java
new file mode 100644
index 000000000..60857a5a5
--- /dev/null
+++ b/proposal/myrmidon/src/make/org/apache/myrmidon/build/AntlibJarTask.java
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) The Apache Software Foundation. All rights reserved.
+ *
+ * This software is published under the terms of the Apache Software License
+ * version 1.1, a copy of which has been included  with this distribution in
+ * the LICENSE.txt file.
+ */
+package org.apache.myrmidon.build;
+
+import org.apache.tools.ant.taskdefs.Jar;
+import org.apache.tools.ant.types.ZipFileSet;
+import org.apache.tools.ant.BuildException;
+import java.io.File;
+
+/**
+ * An Ant 1.x task to assemble a Myrmidon Antlib.
+ *
+ * @author <a href="mailto:adammurdoch@apache.org">Adam Murdoch</a>
+ * @version $Revision$ $Date$
+ */
+public class AntlibJarTask
+    extends Jar
+{
+    private File m_roleDescriptor;
+    private File m_typeDescriptor;
+    private File m_serviceDescriptor;
+
+    public void setRolesDescriptor( final File roleDescriptor )
+    {
+        m_roleDescriptor = roleDescriptor;
+    }
+
+    public void setDescriptor( final File typeDescriptor )
+    {
+        m_typeDescriptor = typeDescriptor;
+    }
+
+    public void setServicesDescriptor( final File serviceDescriptor )
+    {
+        m_serviceDescriptor = serviceDescriptor;
+    }
+
+    public void execute() throws BuildException
+    {
+        maybeAddFile( m_roleDescriptor, "META-INF/ant-roles.xml" );
+        maybeAddFile( m_typeDescriptor, "META-INF/ant-descriptor.xml" );
+        maybeAddFile( m_serviceDescriptor, "META-INF/ant-services.xml" );
+
+        super.execute();
+    }
+
+    private void maybeAddFile( final File file, final String path )
+    {
+        if( file == null )
+        {
+            return;
+        }
+        if( ! file.isFile() )
+        {
+            throw new BuildException( "File \"" + file + "\" does not exist or is not a file." );
+        }
+
+        // Create a ZipFileSet for this file, and pass it up.
+        final ZipFileSet fs = new ZipFileSet();
+        fs.setDir( file.getParentFile() );
+        fs.setIncludes( file.getName() );
+        fs.setFullpath( path );
+        addFileset( fs );
+    }
+}
diff --git a/proposal/myrmidon/src/manifest/core-ant-descriptor.template b/proposal/myrmidon/src/manifest/ant-descriptor.template
similarity index 100%
rename from proposal/myrmidon/src/manifest/core-ant-descriptor.template
rename to proposal/myrmidon/src/manifest/ant-descriptor.template
diff --git a/proposal/myrmidon/src/manifest/builtin-ant-roles.template b/proposal/myrmidon/src/manifest/ant-roles.template
similarity index 100%
rename from proposal/myrmidon/src/manifest/builtin-ant-roles.template
rename to proposal/myrmidon/src/manifest/ant-roles.template