How can I get the Behat integration working with the current code?

I just tried and failed to get the Behat stuff working. Here's what I did:

1. upgrade MAMP to latest version with PHP 5.4
2. install PHPUNit using PEAR
3. create a directory and clone the moodle-behat-features repo into it from moodlehq's github page
4. cd into the directory
5. run curl http://getcomposer.org/installer | php
6. run php composer.phar install

I got this error:

[LogicException]
Can not find "moodlehq/behat-contexts-dev-master" package in registered repositories

Any ideas? I've just learned Ruby and I really don't want to develop any more code without having Behat support working. Cucumber tests in Ruby have spoiled me! (http://cukes.info/)