I thought that might be the case. I was hoping though that by some chance there was a simple setting that I was missing.
Could you post a link to the answerhub issue when you create it so I can add my vote.
Don’t you find this to be unnecessary extra work? You have to flatten out all your layers, copy the alpha, save the new file, etc. Most of it can possibly be automated with an action, but you still have to do some extra steps every time you make a change.