The PDO driver in PHP for MSSQL unfortunately does not support transactions. However, due to the way that Zend Framework is designed we can support it anyway.

Index: C:/Development/ibt/portal/trunk/lib/ZendFramework/library/Zend/Db/Adapter/Pdo/Mssql.php
===================================================================
--- C:/Development/ibt/portal/trunk/lib/ZendFramework/library/Zend/Db/Adapter/Pdo/Mssql.php (revision 112)
+++ C:/Development/ibt/portal/trunk/lib/ZendFramework/library/Zend/Db/Adapter/Pdo/Mssql.php (revision 113)
@@ -314,4 +314,41 @@
         return (int)$this->fetchOne($sql);
     }
 
+    /**
+     * Begin a transaction.
+     *
+     * It is necessary to override the abstract PDO transaction functions here, as
+     * the PDO driver for MSSQL does not support transactions.
+     */
+    protected function _beginTransaction()
+    {
+        $this->_connect();
+        $this->_connection->exec('BEGIN TRANSACTION');
+        return true;
+    }
+
+    /**
+     * Commit a transaction.
+     *
+     * It is necessary to override the abstract PDO transaction functions here, as
+     * the PDO driver for MSSQL does not support transactions.
+     */
+    protected function _commit()
+    {
+        $this->_connect();
+        $this->_connection->exec('COMMIT TRANSACTION');
+        return true;
+    }
+
+    /**
+     * Roll-back a transaction.
+     *
+     * It is necessary to override the abstract PDO transaction functions here, as
+     * the PDO driver for MSSQL does not support transactions.
+     */
+    protected function _rollBack() {
+        $this->_connect();
+        $this->_connection->exec('ROLLBACK TRANSACTION');
+        return true;
+    }
 }

Please consider this for future Zend - it's extremely important for those of us who use MSSQL!