Bummer...
Since we know they had to get it in somehow, we have assume they installed the mechanism first and then installed the face and needle. The more I think about it, that makes sense why they went to the trouble to print the small calibration dot at about -8kmh. Here is an idea...I am just trying to be creative now, so I'm guessing...
Perhaps you could gently pop the needle over the stop post. Then tap the case to see where the needle comes to rest naturally. This would be your calibration point when you go to reassemble the needle later. Then you can remove the needle and face, so the mechanism will come out.
To hold the aluminum drag cup while you twist the needle off, it's possible to use a pinky finger through one of the light holes in the case. It takes some feeling to find it, but I know it's possible, as I've done it.
Anyway...just a thought. The only other option would be to bend the reset shaft, which won't help when you go to reassemble everything. Or, take 1/4" or so off the end of the shaft.
Be sure to let us know what works.