Logitech G27 Race Wheel, F-Zero GX Problems

[schism]

I'm having issues getting my Logitech G27 race wheel and pedals working appropriately with F-Zero GX on Dolphin. Basically, the buttons appear to be working, and the wheel itself appears to be working, however the acceleration and break pedals do nothing. I did some googling and searching on the forums to find a couple things. The first thing I found was this thread, detailing the set up I should be using for a G27 race wheel. So I tried that with the latest release of Dolphin (4.0-9224), and the results were the same. The buttons were responsive, the wheel appeared functional, and the pedals didn't work at all. I then found this thread which stated that  I need an older version of Dolphin, in this case 4.0-4523, in order for my Logitech G27 to work properly with Dolphin. I downloaded it and I did not have success. Anyone have any ideas? I feel like I've tried everything, and I can confirm the controller itself is not broken.

[skid]

The accelerator pedal should be mapped to Main Stick Up and the brake pedal should be mapped to Main Stick Down. I think the G27 might need to be set up as a Combined Axis controller as well.