I am posting because I have not found a thread to address or sort this issue. I keep expecting this issue to be fixed with new releases of AMS2 but so far no love. I have a Fanatec DD1 on driver 381, all buttons and the sequential paddle shifters work in AMS2 (using Fanatec's Universal Hub). I have a Thrustmaster TH8A shifter plugged in through USB and that works in game as a gated shifter as well. I have a Derek Speare Design Short Throw Pro, Sequential Shifter purchased in April of 2017 (shows up in windows game controllers as: " JoyWarrior A8-8"), that has not and will not work in AMS2. I have created a "Custom" "Make" profile as I saw in one of the treads I found and I still cannot get this DSD Seq shifter to map. It works in all my other Sims. Please help = )...
Not sure how much help this will be as it's a bit of a workaround, but have you tried using a key mapping software (Joy2Key, AutoHotKey, XPadder, etc)? You could then map both the Fanatec paddles and your DSD shifter to the same keyboard keys, for example [ for downshift and ] for upshift and use those keys in AMS2 for shifting.
Thanks Duncan, Good to know about. Not really interested in adding third party apps to address something that should just work.