diff --git a/library/HTMLPurifier/Config.php b/library/HTMLPurifier/Config.php
index 67780cbd..6e078eb7 100644
--- a/library/HTMLPurifier/Config.php
+++ b/library/HTMLPurifier/Config.php
@@ -105,11 +105,13 @@ class HTMLPurifier_Config
      */
     function create($config) {
         if (is_a($config, 'HTMLPurifier_Config')) {
-            $config = $config->conf; // create a clone
+            // pass-through
+            return $config;
         }
         $ret = HTMLPurifier_Config::createDefault();
         if (is_string($config)) $ret->loadIni($config);
         elseif (is_array($config)) $ret->loadArray($config);
+        if (isset($revision)) $ret->revision = $revision;
         return $ret;
     }
     
diff --git a/library/HTMLPurifier/HTMLDefinition.php b/library/HTMLPurifier/HTMLDefinition.php
index dfe71114..d0a1f1c7 100644
--- a/library/HTMLPurifier/HTMLDefinition.php
+++ b/library/HTMLPurifier/HTMLDefinition.php
@@ -204,6 +204,27 @@ class HTMLPurifier_HTMLDefinition extends HTMLPurifier_Definition
     
     
     
+    // RAW CUSTOMIZATION STUFF --------------------------------------------
+    
+    /**
+     * Adds a custom attribute to a pre-existing element
+     */
+    function addAttribute($element_name, $attr_name, $def) {
+        $module =& $this->getAnonymousModule();
+        $element =& $module->addBlankElement($element_name);
+        $element->attr[$attr_name] = $def;
+    }
+    
+    var $_anonModule;
+    
+    function &getAnonymousModule() {
+        if (!$this->_anonModule) {
+            $this->_anonModule = new HTMLPurifier_HTMLModule();
+            $this->_anonModule->name = 'Anonymous';
+        }
+        return $this->_anonModule;
+    }
+    
     
     // PUBLIC BUT INTERNAL VARIABLES --------------------------------------
     
@@ -234,6 +255,14 @@ class HTMLPurifier_HTMLDefinition extends HTMLPurifier_Definition
      */
     function processModules($config) {
         
+        if ($this->_anonModule) {
+            // for user specific changes
+            // this is late-loaded so we don't have to deal with PHP4
+            // reference wonky-ness
+            $this->manager->addModule($this->_anonModule);
+            unset($this->_anonModule);
+        }
+        
         $this->manager->setup($config);
         $this->doctype = $this->manager->doctype;
         
diff --git a/tests/HTMLPurifier/HTMLDefinitionTest.php b/tests/HTMLPurifier/HTMLDefinitionTest.php
index b9c77e07..d95a6da9 100644
--- a/tests/HTMLPurifier/HTMLDefinitionTest.php
+++ b/tests/HTMLPurifier/HTMLDefinitionTest.php
@@ -52,6 +52,23 @@ class HTMLPurifier_HTMLDefinitionTest extends UnitTestCase
         
     }
     
+    function test_addAttribute() {
+        
+        $config = HTMLPurifier_Config::create(array(
+            'HTML.DefinitionID' => 'HTMLPurifier_HTMLDefinitionTest->test_addAttribute'
+        ));
+        $config->revision = 9;
+        $def =& $config->getHTMLDefinition(true);
+        $def->addAttribute('span', 'custom', 'Enum#attribute');
+        $def = $config->getHTMLDefinition();
+        
+        $purifier = new HTMLPurifier($config);
+        $input = '<span custom="attribute">Custom!</span>';
+        $output = $purifier->purify($input);
+        $this->assertIdentical($input, $output);
+        
+    }
+    
 }
 
 ?>
\ No newline at end of file