[spidey]

Please stop thinking of this as a "temper tantrum". If he indeed has separation anxiety, it is an anxiety issue related to his associating being in his crate with you going away, it is not a temper tantrum. "Temper tantrum" implies that he is doing this on purpose, if he is anxious, he cannot help it and it will not help you deal with this properly if you continue thinking of this as something other than what it is, an anxiety problem. Have you actually gone through appropriate crate training with him? Most dogs do not instantly accept being crated, especially if they are being crated and then left alone. You need to train the dog to accept crating - if your dog has both separation anxiety AND you have not crate trained him, then these two things are feeding each other and making him very anxious indeed.

There are quite a few threads here about crate training separation anxiety if you do a search, I'd also suggest that you pick up a copy of "I'll Be Home Soon" by Patricia McConnell, which is a great book about how to deal with separation anxiety, and Ian Dunbar's "Before & After You Get Your Puppy" has a crate training section which is suited to dogs of all ages.