Sega 6-button controller

[Lylat1an]

I'm trying to use a 6-button controller in Steam's Sega Mega Drive & Genesis Classics, but when I try to configure the controller it detects the D-pad as a joystick instead of 4 buttons.

Is this the way it's supposed to be, or can it be changed with a firmware update?

I'm using a Retrode 2 with firmware .20-Beta