Mirror IU a.jre.javase from upstream Platform p2 repository

The installable unit a.jre.javase from the Eclipse Platform
repository re-provides Java packages from the JRE that are required by
Jetty bundles. This is required to create a self-contained p2
repository for the RAP Runtime features.
diff --git a/releng/org.eclipse.rap.target.releng/pom.xml b/releng/org.eclipse.rap.target.releng/pom.xml
index e3e0d97..08bd690 100644
--- a/releng/org.eclipse.rap.target.releng/pom.xml
+++ b/releng/org.eclipse.rap.target.releng/pom.xml
@@ -25,6 +25,7 @@
     <tycho-version>0.15.0</tycho-version>
     <signing-plugin-version>1.0.5</signing-plugin-version>
     <base-platform>4.3milestones/S-4.3M2-201209201300/</base-platform>
+    <base-platform-repository>http://download.eclipse.org/eclipse/updates/${base-platform}</base-platform-repository>
   </properties>
 
   <prerequisites>
@@ -48,7 +49,7 @@
     <repository>
       <id>base-platform-repository</id>
       <layout>p2</layout>
-      <url>http://download.eclipse.org/eclipse/updates/${base-platform}</url>
+      <url>${base-platform-repository}</url>
     </repository>
     <repository>
       <id>extra-dependencies-repository</id>
diff --git a/releng/org.eclipse.rap.target.releng/repository/pom.xml b/releng/org.eclipse.rap.target.releng/repository/pom.xml
index 13e89d1..1ceca78 100644
--- a/releng/org.eclipse.rap.target.releng/repository/pom.xml
+++ b/releng/org.eclipse.rap.target.releng/repository/pom.xml
@@ -35,6 +35,36 @@
           <compress>true</compress>
         </configuration>
       </plugin>
+      <plugin>
+        <groupId>org.eclipse.tycho.extras</groupId>
+        <artifactId>tycho-p2-extras-plugin</artifactId>
+        <version>${tycho-version}</version>
+        <executions>
+          <execution>
+            <phase>prepare-package</phase>
+              <goals>
+                <goal>mirror</goal>
+              </goals>
+          </execution>
+        </executions>
+        <configuration>
+          <source>
+            <repository>
+              <url>${base-platform-repository}</url>
+              <layout>p2</layout>
+            </repository>
+          </source>
+          <ius>
+            <iu>
+              <id>a.jre.javase</id>
+            </iu>
+          </ius>
+          <includeOptional>false</includeOptional>
+          <includeNonGreedy>false</includeNonGreedy>
+          <latestVersionOnly>true</latestVersionOnly>
+          <mirrorMetadataOnly>true</mirrorMetadataOnly>
+        </configuration>
+      </plugin>      
     </plugins>
   </build>