[TYPO3-english] Autoloader doesn't work for BE-Modules

[hinterindien at gmx.net]

Hi list!

I couldn't get the autoloader running. 

I have an installation of typo3 4.5, an own BE-Extension with a file ext_autoload.php in the main folder of the extension. The extension is running and works. But if I replace the "require_once"-Statement inside my code by the appropriate entry in ext_autoload.php, PHP throws a fatal error "Class not found". 

Clearing caches didn't help. 

Do I have to activate the autoloader? Register my extension with the autoloader? I didn't find any hints in the documentation...

Thanks for any helpful ideas

Nicolai