The solution for #43 breaks magento maintenance mode.

[JerryBra]

The solution for #43 breaks magento maintenance mode due
Steps to reproduce:
Create the file maintenance.flag in magento root

Expected result:
Magentos 503 maintenance page is displayed

Actual result:
500 Error

Fatal error: Uncaught exception 'BadMethodCallException' with message 
'Call to a member function getOptions() on a non-object (null)' 
in magento/app/Mage.php:337
Stack trace:
#0 magento/errors/processor.php(140): Mage::getBaseDir()  
#1 magento/errors/503.php(29): Error_Processor->__construct()
#2 magento/index.php(60): include()
#3 {main}