Sensible Plug & Play

Hi Guys,
new here this is my 1st post so go easy........
recently bought a plug play sensible soccer unit. Its the mega drive version thats on it along with cannon fodder mega lo mania.
www.amazon.co.uk/Sensible-Soccer-Plus-Plug-Games/dp/B000B600X0
I remember playing it using a joystick rather than a joypad. So much more fun with the joystick the suction cups stuck to a Match annual ;D
My Q is...any1 got any idea if i could disconnect the joypad attach a proper joystick?
Any help or links would be much appreciated , thanks