[XH2S Time Lapse]

How do you change ISO when during the interval shooting. Since I cannot assign the ISO to a command wheel I'm left with aperture and shutter speed only. Thanks for any advice. 

[X-H2S Can't assign ISO to a command wheel.]

What is even more frustrating is that when in interval mode (time-lapse) I cannot change the ISO to adjust for changing light. It is crucial to shoot time lapses fully manual, but I can only adjust the shutter speed and aperture (which I don't want to). Does anyone know how to fix this? Thanks