diff --git a/proposal/myrmidon/antlib.xml b/proposal/myrmidon/antlib.xml
index fdb09465a..75e7287f4 100644
--- a/proposal/myrmidon/antlib.xml
+++ b/proposal/myrmidon/antlib.xml
@@ -24,7 +24,7 @@ Legal:
   <property name="lib.dir" value="lib"/>
 
   <!-- directory where you place generated code -->
-  <property name="gen.dir" value="gen"/>
+  <property name="gen.dir" value="${build.dir}/gen"/>
 
   <property name="antlib.name" value="NONAME"/>
   <property name="antlib.include" value="org/apache/antlib/${antlib.name}/**"/>
@@ -66,7 +66,7 @@ Legal:
   <target name="jar" depends="xdoclet">
     <jar jarfile="${build.lib}/${antlib.name}.atl" basedir="${build.classes}">
       <include name="${antlib.include}" />
-      <zipfileset dir="${manifest.dir}" fullpath="META-INF/ant-descriptor.xml">
+      <zipfileset dir="${gen.dir}" fullpath="META-INF/ant-descriptor.xml">
         <include name="${antlib.descriptor}"/>
       </zipfileset>
     </jar>
diff --git a/proposal/myrmidon/build.xml b/proposal/myrmidon/build.xml
index 60cb92871..f8f5c064b 100644
--- a/proposal/myrmidon/build.xml
+++ b/proposal/myrmidon/build.xml
@@ -59,6 +59,8 @@ Legal:
   <property name="dist.lib" value="${dist.dir}/lib"/>
   <property name="dist.ext" value="${dist.dir}/ext"/>
 
+  <property name="gen.dir" value="${build.dir}/gen"/>
+
   <property name="test.dir" value="${build.dir}/test"/>
   <property name="test.working.dir" value="${test.dir}/testcases"/>
   <property name="test.classes" value="${test.dir}/classes"/>