This is the firebox:
http://www.presonus.com/products/FireBoxI think if I understand you correctly, if I use SPDIF, then everything audio related can be handled through the Firebox interface. I'd still have to run a USB to the PC, it just wouldn't be for audio purposes, but it'd still work to control my interface?
The only issue with that is running another cable, which I was trying to avoid. But it's definitely a solid backup option if the ASIO4ALL doesn't solve my issue.