i have fitted these light to my girlfriends XTZ660. I used a switched powersupply (took it from the original headlight) and a seperate switch to power them. Every time I use the switch you cycle between the functions. In the same way as a Petzl headlight or a LED hand torch works.

It is not possible to only use one mode. You have to toggle through the modes to go to the one you want to use after you have switched off the light or the bike. But it is possible to trick this (read the comments):

https://www.youtube.com/watch?v=t2emfod4MaA