I've documented the simplest method here http://elearning.zhaw.ch/moodle/course/view.php?id=611
This discusseion has more details http://moodle.org/mod/forum/discuss.php?d=25640
Here are more involved discussions http://moodle.org/mod/forum/discuss.php?d=42458 and http://moodle.org/mod/forum/discuss.php?d=143746
This discusseion has more details http://moodle.org/mod/forum/discuss.php?d=25640
Here are more involved discussions http://moodle.org/mod/forum/discuss.php?d=42458 and http://moodle.org/mod/forum/discuss.php?d=143746