Throwing in the towel... ((long))

You may have no choice but to return the dog to the breeder or re-home it. It may seem unfair to surrender the dog but it would be more unfair to your other dogs and to the dog in question. By returning the dog, he will be given another chance to find a home where he fits in.
 

You probably already know this but...
 
You have an "alpha" problem that is not easy to break and seldom
is long term even if you do see results from your initial time investment
in behavioral training.
 
Your older male still has some old "alpha" tendencies and the younger
dog naturally knows this and is trying to dominate.
 
I've been in the "dog business" for more than 20 years and know first hand
what an "all out" fight for domination can become. 
 
I've seen many owners lose a favorite pet because the new alpha dog decided
it was "his time".
 
When you find your behavioral specialist, if he/she tells you that you can control
this behavior you need to get a second opinion.
 
You simply cannot gain control of this situation until one or both of your dogs simply
give up the alpha position and submit, which seldom occurs, except in wild dogs and
wolves.  House dogs are a different story because of the limited space they enjoy.
 
Do the safe, and right thing for your dogs, return your pup to the breeder or both of
you will be miserable for years.

Would reestabling yourself as pack leader work, or are the dogs too far gone to solve matters?  You definitely need a professional's help.
 
I read that when you punish the dominant dog, you just make the submissive dog think it's all right if he tries to be assertive.  I also read that if the dogs are alone they are likely not to fight because you are not there to back up the submissive dog.
 
I don't know if any of this helps, but I'm reading about amichien training, but your dogs problem might be too severe.
 
 

I also read that if the dogs are alone they are likely not to fight because you are not there to back up the submissive dog.

 
I have found this to be absolutely true with my two girls.  They have never had a fight when we weren't around or even nearby.  I say this with certainty because based on the way they fight, they would a) have wounds and b) have never ended a fight without intervention on our part.  I'm not sure of the psychology behind it all, but I do think one reason is because they don't interact much when we're not there, so it's more stable.

I also read that if the dogs are alone they are likely not to fight because you are not there to back up the submissive dog.

 
While that is true sometimes, it isn't always.  A change in pack hierarchy can happen quickly and with a minimum of ritualistic fighting.  When the same dogs are fighting repeatedly, and drawing blood, it can escalate to the point of death, and often causes severe trauma emotionally, too.  This may just be two dogs that can't get along, but it may also be two dogs too similar in status, and determined to get to the "corner office".