diff --git a/reference/strings/functions/substr-replace.xml b/reference/strings/functions/substr-replace.xml
index 00fd077c88..8c8ac525c0 100644
--- a/reference/strings/functions/substr-replace.xml
+++ b/reference/strings/functions/substr-replace.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.5 $ -->
+<!-- $Revision: 1.6 $ -->
 <!-- splitted from ./en/functions/strings.xml, last change in rev 1.2 -->
   <refentry id="function.substr-replace">
    <refnamediv>
@@ -41,7 +41,11 @@
      <parameter>string</parameter> at which to stop replacing. If it
      is not given, then it will default to strlen(
      <parameter>string</parameter> ); i.e. end the replacing at the
-     end of <parameter>string</parameter>.
+     end of <parameter>string</parameter>. Of course, if
+     <parameter>length</parameter> is zero then this function will have the
+     effect of inserting <parameter>replacement</parameter> into
+     <parameter>string</parameter> at the given 
+     <parameter>start</parameter> offset.
     </para>
     <para>
      <example>