All this week we've been bringing you a series of reports about the Darfur you didn't know. Now Mohammed Vall follows the trail of the nomadic Arabs of Darfur. They are sometimes wrongfully characterised as Janjaweed, the government backed militia involved in much of the violence of the past 4 years. But as Mohammed discovered, the Rizegat Bedouin are themselves struggling to preserve their way of life in a region torn apart by the conflict.