composer autoloader psr-0 namespaces

composer autoloader psr-0 namespaces

I have create a custom composer package but I am havinh troubles to set
the correct autoload options for it.
All my classes are under "MyNamespace/Common" namespace. So for exemple
for including my ArrayHelper class I do use
Mynamespace/Common/Helper/ArrayHelper.
This is the relevant part of my composer.json
"autoload": {
"psr-0": { "MyNamespace\\": "" }
}
I have read this: http://getcomposer.org/doc/04-schema.md#autoload Any
help. Thank you.