diff --git a/reference/mbstring/ini.xml b/reference/mbstring/ini.xml
index f246594980..17fe5287b1 100644
--- a/reference/mbstring/ini.xml
+++ b/reference/mbstring/ini.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.2 $ -->
+<!-- $Revision: 1.3 $ -->
 <section id="mbstring.configuration">
  &reftitle.runtime;
  &extension.runtime;
@@ -100,6 +100,18 @@
      character to substitute for invalid character encoding.
     </simpara>
    </listitem>
+   <listitem id="ini.mbstring.func-overload">
+    <simpara>
+     <literal>mbstring.func_overload</literal>overload(replace) single byte
+     functions by mbstring functions. <function>mail</function>,
+     <function>ereg</function>, etc. are overloaded by
+     <function>mb_send_mail</function>, <function>mb_ereg</function>, etc.
+     Possible values are 0, 1, 2, 4 or a combination of them.
+     For example, 7 for overload everything.
+      0: No overload, 1: Overload <function>mail</function> function,
+      2: Overload str*() functions, 4: Overload ereg*() functions.
+    </simpara>
+   </listitem>
   </itemizedlist>
  </para>
  <para>