Playing 1.1 right now (well I would be if the game didn't crash inevitably early on - I *really* need that patch), anyway, I just got a twon-ha and as I recall twon-has can jump. Also the icon suggests that pressing the left mouse button / A button should make the twon-ha jump while you're moving. Well, no matter what I try, I seem to be unable to make the twon-ha jump. It just keeps on running regularly, no matter what I try.

Am I doing something wrong or is it currently impossible to make the twon-ha jump in version 1.1?

Could it really jump in the origin version? Anyway, i guess there is no need to jump, the Twon-Ha can climb most hillsides and stairs an so on, without jumping. The only thing you have to ride around are fences.

It could definitely jump in the original Outcast and it was a really funny part of the whole Twôn-ha-riding to jump around. Sure, theoretically you could just walk around all obstacles in the game, but where's the fun in that? It seems like the good old Twôn-ha is bugged once again...
This issue has to be solved by the developers.

Thanks. Glad to hear it. :)