Retro-Donald USB Joystick adapter

[scrappysphinx]

Hi all, i have one of the Retro-Donald USB joystick adapters. It all works perfectly well with the majority of controllers i've connected to it however it only supports 2 buttons. I was hoping to use the Sega megadrive controller with it which has 3 or 6 buttons plus a start button.

So does anyone know if you can make it support more buttons or is it a case of having another adapter?

Thanks