I see. OKAY.
I can only advise this:
-plug the second FIRE to pin no.2 (direction DOWN in Joy port 1)(disconnect from pin No.6)
-in the game, set the menu to be under the [<-] key (arrow pointing left)
the downward direction (activated with the second Joy button) on Joy port 1 will open and close the menu
xD
Ps
I assumed that you made this custom Joystick yourself.
+1