diff --git a/library/Icinga/Authentication/User/LdapUserBackend.php b/library/Icinga/Authentication/User/LdapUserBackend.php
index b26b8aad7..930ac4c99 100644
--- a/library/Icinga/Authentication/User/LdapUserBackend.php
+++ b/library/Icinga/Authentication/User/LdapUserBackend.php
@@ -208,6 +208,24 @@ class LdapUserBackend extends LdapRepository implements UserBackendInterface, In
         return $query;
     }
 
+    /**
+     * Initialize this repository's virtual tables
+     *
+     * @return  array
+     *
+     * @throws  ProgrammingError    In case $this->userClass has not been set yet
+     */
+    protected function initializeVirtualTables()
+    {
+        if ($this->userClass === null) {
+            throw new ProgrammingError('It is required to set the object class where to find users first');
+        }
+
+        return array(
+            'user' => $this->userClass
+        );
+    }
+
     /**
      * Initialize this repository's query columns
      *
@@ -317,29 +335,6 @@ class LdapUserBackend extends LdapRepository implements UserBackendInterface, In
         return ((int) $value) >= $bigBang->diff($now)->days;
     }
 
-    /**
-     * Validate that the requested table exists
-     *
-     * This will return $this->userClass in case $table equals "user".
-     *
-     * @param   string              $table      The table to validate
-     * @param   RepositoryQuery     $query      An optional query to pass as context
-     *                                          (unused by the base implementation)
-     *
-     * @return  string
-     *
-     * @throws  ProgrammingError                In case the given table does not exist
-     */
-    public function requireTable($table, RepositoryQuery $query = null)
-    {
-        $table = parent::requireTable($table, $query);
-        if ($table === 'user') {
-            $table = $this->userClass;
-        }
-
-        return $table;
-    }
-
     /**
      * Validate that the given column is a valid query target and return it or the actual name if it's an alias
      *