I am not familiar with spitfire code but I can tell you electrically what needs to happen.
So here is the deal, you will only need 2 outputs, one for the analog x axis and one for the analog y axis. when the anolog stick is relaxed and not being pressed the signals for the x and y axis will be halfway between +V and ground. When the stick is being pressed in the y direction the Y axis output will be either +V or ground. Same goes for the x axis.
so in order to do the macro you want to do, the output of the spit fire will need to be on 2 pins one goes the x axis middle pin and one to the y axis to middle pin:
I = Input +V = output high G = output low
X Y
I +V (Down)
+V +V (Down+Left)
+V I (Left)
+V G (Up+Left)
I G (Up)
G G (Up + Right)
G I (Right)
G +V (Down + Right)
The above sequence may not be correct, whether or not up is Ground on y axis needs to be confirmed. the above sequence is just a demonstration of the concept, you will need to confirm your own values for the directions.