The certificates are fake, anyone can make them up. It's a good scam tactic because most people take their word for it without taking the time to investigate.
Unilever is working on an authentic and proven form of hoodia gordonii, in cooperation with PhytoPharm, that will be brought to the US but only after extensive trials have proven the product both safe and effective. Unilever makes SlimFast, so we'll probably see it in diet food products.
When the real thing is available to us, we'll shout it from the rooftops. Until then, avoid anything that claims to include hoodia.