They show up as different drugs. Reports always release the drug result i.e. dbol, nandralone etc.. I'm not sure about trenbolone as I've never seen a reported positive for it but I'd assume they will identify it correctly.
This is a reason why a lot of atheletes prefer short acting testosterone. They test for an acceptible range (which can be quite high - although not for the guys on this board) so one can always get away with some extra supplementation as long as it's identical to what they expect to find in the body.
My advice is don't push it. The best atheletes in the world with the best science can't guarantee a pass (that's why they pull out just before the olympics w/ injuries).