That error was reported by @Jayce . Wait for @alanfox2000 to update the latest APO Driver installer.So, I managed to find the control panel, but there seems to be no option to separate the outputs.
Also, I'm now getting error in APO driver installer, 'EXE and MSI signature mismatch' or something
I don't have UAD drivers installed, therefore I can't help you much right now. In a few days, I will have a dell 7375. I expect the audio system to be quite similar to your system. I might help you then.