receive data from autoloading file

[eluser]mohfeza code ignitor[/eluser]
I read that tutorial earlier. I build a custom config file named 'amazonconfig' and add into autoload.php as $autoload['config'] =array('amazonconfig');. Tutorial said- I don't need to load 'amazonconfig' file manually. my question is why i am not getting data from amazonconfig.php if i do $var. That means autoloading is not working. Please give me solution