MPPDF-26 : document the need for different files for different items.

Thank you Rick.

git-svn-id: https://svn.apache.org/repos/asf/maven/maven-1/plugins/trunk@232440 13f79535-47bb-0310-9956-ffa450edef68

pdf/xdocs/index.xml

@@ -16,20 +16,19 @@
  * limitations under the License.
  */
  -->
-
 <document>
-    <properties>
-        <title>Maven PDF Plug-in</title>
-        <author email="jason@zenplex.com">Jason van Zyl</author>
-        <author email="dion@apache.org">dIon Gillard</author>
-    </properties>
-    <body>
-        <section name="Maven PDF Plug-in">
-            <p>This plug-in allows you to generate a PDF version of your project's
-        documentation.</p>
-            <p>There is a known problem with the PDF generation tool (Apache's FOP)
-        in that it doesn't allow for table structures with automatic column
-        widths to be generated. Widths are uniformly distributed.</p>
-        </section>
-    </body>
+  <properties>
+    <title>Maven PDF Plug-in</title>
+    <author email="jason@zenplex.com">Jason van Zyl</author>
+    <author email="dion@apache.org">dIon Gillard</author>
+  </properties>
+  <body>
+    <section name="Maven PDF Plug-in">
+      <p>This plug-in allows you to generate a PDF version of your project's documentation.</p>
+    </section>
+    <section name="Know issues">
+      <p>There is a known problem with the PDF generation tool (Apache's FOP) in that it doesn't allow for table structures with automatic column        widths to be generated. Widths are uniformly distributed.</p>
+      <p>Due to several problems, it is actually impossible to reference the same file in different items in navigation.xml. You must define another navigation file (using the property <a href="properties.html">"maven.pdf.navigationFile"</a>) which you'll use only with the PDF plug-in. This navigation cannot define several items with the same href.</p>
+    </section>
+  </body>
 </document>