Uploading file in behat using relative path

Is it possible to upload file during test using behat and Selenium2 with relative path? I am doing it like this in my Page Class:

 $element = $this->getElement('Upload file');
 $element->attachFile('full_path_to_file');

When I am using full path it works just fine, but it doesn't work with relative path. Can I somehow configure it in behat.yaml?