diff -aur apt.orig/apt-pkg/algorithms.cc apt/apt-pkg/algorithms.cc
--- apt.orig/apt-pkg/algorithms.cc	2012-06-17 11:00:29.000000000 +0200
+++ apt/apt-pkg/algorithms.cc	2012-06-17 13:40:05.000000000 +0200
@@ -1497,6 +1497,14 @@
    if (Fetcher.Setup(&Stat, _config->FindDir("Dir::State::Lists")) == false)
       return false;
 
+   // Run scripts
+   RunScripts("APT::Update::Pre-Invoke");
+
+   // Refresh source lists, Pre-Invoke might change content
+   if (_config->FindB("APT::Update::List-Refresh",false) == true)
+       if (List.ReadMainList() == false)
+           return false;
+
    // Populate it with the source selection
    if (List.GetIndexes(&Fetcher) == false)
 	 return false;
@@ -1509,14 +1517,13 @@
 /* This is a simple wrapper to update the cache with a provided acquire
  * If you only need control over Status and the used SourcesList use
  * ListUpdate method instead.
+ * If you are calling AcquireUpdate directly you should call
+ * APT::Update::Pre-Invoke sripts on your own and reload source lists
+ * if needed.
  */
 bool AcquireUpdate(pkgAcquire &Fetcher, int const PulseInterval,
 		   bool const RunUpdateScripts, bool const ListCleanup)
 {
-   // Run scripts
-   if (RunUpdateScripts == true)
-      RunScripts("APT::Update::Pre-Invoke");
-
    pkgAcquire::RunResult res;
    if(PulseInterval > 0)
       res = Fetcher.Run(PulseInterval);
diff -aur apt.orig/doc/apt.conf.5.xml apt/doc/apt.conf.5.xml
--- apt.orig/doc/apt.conf.5.xml	2012-06-17 01:35:56.000000000 +0200
+++ apt/doc/apt.conf.5.xml	2012-06-17 13:41:03.000000000 +0200
@@ -243,6 +243,10 @@
      </para></listitem>
      </varlistentry>
 
+     <varlistentry><term><option>Update</option></term>
+     <listitem><para>Thig group is used in update phase. See UPDATE group below.</para></listitem>
+     </varlistentry>
+
      <varlistentry><term><option>Cache-Start</option></term><term><option>Cache-Grow</option></term><term><option>Cache-Limit</option></term>
      <listitem><para>APT uses since version 0.7.26 a resizable memory mapped cache file to store the available
      information. <literal>Cache-Start</literal> acts as a hint of the size the cache will grow to,
@@ -557,6 +561,46 @@
    </variablelist>
  </refsect1>
 
+
+ <refsect1><title>The Update Group</title>
+   <para>The <literal>Update</literal> group of options controls the
+   update phase.</para>
+
+   <variablelist>
+     <varlistentry><term><option>Pre-Invoke, Post-Invoke</option></term>
+     <listitem><para>
+     This is a list of shell commands to run before/after the package index files
+     are synchronized from their sources. This must be specified in list notation.
+     The commands are invoked in order using /bin/sh.
+     </para></listitem>
+     </varlistentry>
+
+   <variablelist>
+     <varlistentry><term><option>Post-Invoke-Success</option></term>
+     <listitem><para>
+     This is a list of shell commands to run after the package index files
+     are successfully synchronized from their sources. This must be specified in list notation.
+     The commands are invoked in order using /bin/sh.
+     This is run immediatelly before Post-Invoke. 
+     </para></listitem>
+     </varlistentry>
+
+   <variablelist>
+     <varlistentry><term><option>List-Refresh</option></term>
+     <listitem><para>
+     If you modify &sources.list; in Pre-Invoke, you should set this boolean value to true.
+     If set to true, then &sources.list; are re-read after Pre-Invoke scripts are run.
+     Default is set to false.
+     Note, that it is not recommended to modify directly main &sources.list, but rather
+     your own file in /etc/apt/sources.list.d directory.
+     This is run immediatelly before Post-Invoke.
+     </para></listitem>
+     </varlistentry>
+
+   </variablelist>
+ </refsect1>
+
+
  <refsect1><title>Directories</title>
 
    <para>The <literal>Dir::State</literal> section has directories that pertain to local