Hi !
I downlaoded a controller.ini for official GC adaptater for Wii U, and when i stick down, it goes up, and reverse.
Here is the ini :
[Nintendo Wii U GameCube Controller Adapter]
VID=057E
PID=0337
Polltype=1
DPAD=1
MultiIn=3
MultiInValue=09
Power=3,0F
A=2,01
B=2,02
X=2,04
Y=2,08
Z=3,02...