I did this myself to my 998, and it cost 50p for the diode.
Procedure is to connect a IN4001 diode from the +ve side of the neutral light to the 'Blue' wire side of the sidestand, with the 'striped' end of the diode connected to the neutral light side.
This has worked well for over 12 months and for 50p, a real bargain.
This way means that the engine operates either when the side stand is up, or when both the sidestand is down and the neutral light is on.
hope this helps