As I said before it's not as easy as that. The driver has a softstart function and a pwm will not work in conjunction with softstart.
Maybe you can get some dimming with 30Hz and an min. on/off ration of maybe 1/30 with simply turning on and off the driver but that is not useful I think.
I'm already working on both a pwm and analog solution but as always I don't have enough time to work on that so I'm progressing very slowly but I'm sure it will work after all. It just takes a "little" more time.