I certainly can appreciate the aggravation you are having. I am not an AMD employee and am only stating what I am about to say base on past issues and knowing how these things work.
While it may be a compatibility issue with newer AMD hardware. The DSP card's maker will likely be the people that fix this issue for you. I have seen these issues with these cards before and most of those companies love to sell you a new one, never updating drivers and firmware for older cards. I can't speak to this company specifically but I would bet that AMD has no way to test with that card, at least not without the involvement of that cards maker. I would absolutely report the bug to AMD, but this is not the place, (unless you get luck and someone here does know what to do) these are community forums. A couple AMD employees do frequent here, but no guarantee they will or won't be able to help. You could try to ask for help here with this official AMD: Email Form
Next I would re-contact support from the company that you bought the cards, maybe there is already a firmware update or new driver that could take care of things? If the person isn't helping you ask if the issue can be escalated to an engineer or the next higher level. I know from past experience though that a lot of the updates they do are in their software and they charge for those upgrades. Unfortunately there is never any guarantee when we buy anything that it will ever support anything beyond what they said it would when we bought it, it's just great that most companies do this, because it's just good business. Hopefully they can offer some good help. Maybe at a minimum work you some kind of better deal, if they don't have a free solution.
I've got totes full of old expensive cards that just are not supported anymore. I know it's beyond rough.
I sure hope you find help with your issue. Maybe someone else will come along with better help. Good luck!