Well, to be clear, all tests have been done on Windows system
a) Emulator Fusion (Megaddrive / Genesis) :Mapping ok for Megadrive controllers (all 4 "Retrode" items shown in the controller selection)
Play ok
b) Emulator Snes9X (SNES) :Mapping ok for SNES controllers
Play ok
c) HyperSpinMapping ok for Megadrive controllers
Mapping ok for SNES controllers
Using NOT WORKING CORRECTLY ok for Megadrive controllers with HyperSpin. The Analogic direction are not usable but few buttons can be used (strange behavior !)
Using ok for SNES controllers with HyperSpin
d) Mame32
You must use TAB key to define controller mapping when a game is launched (Joystick option selected previously into the Mame32 interface)
Possible to do mapping with SNES controllers (it rocks because all buttons are usable !!!)
Impossible to do mapping with Megadrive controllers
e) To concludeMaybe a new firmware version can allow : Retrode SNES 1, Retrode SNES 2, Retrode SEGA 1, Retrode SEGA 2 instead of the 4 "Retrode" items listed using Fusion selection
Maybe something to dig and to improve into the firmware for Megadrive / Genesis controller

Tests done on Windows Vista Family edition and Windows Xp ...
Regards
Grégory