Well, since we're mods, we don't have access to the back end/game code and so on, so we can only make wild guesses about the reasons it's broken.
My best guess is that your gamepad would count as the "generally supported" kind, but with issues. A while ago, they talked about how it's impossible to ensure a perfect compatibility with every single gamepad on Earth and you've probably fallen in the not perfectly compatible zone.
From there on, I see two solutions:
- If you haven't already, try submitting a ticket, starting from Bscotch
Support section. Thing is, it may not be fixed (or not before a while) if it takes a lot of time to fix (they're a small company, so sinking hours of work on a fix for a few people may not be worth it)
- The second solution involves a gamepad remapper software. I'm not knowledgeable in the software side of it, but there should be some stuff that allow you to either change actions associated with buttons (try reversing up and down) OR to emulate a Xbox gamepad (or similar) so that it works for you.