Setting ISO value through viewfinder (60D and 600D)

Hi there.

I am thinking of buying a DSLR, and was playing around with the 60D and 600D at a local store today. With both cameras, I switched to manual mode, looked through the VF and went through different shutter speeds and apertures. However, I noticed that I am not able to change the ISO value without losing other data in VF. I had to half press to bring them back, and only then I could determine whether I should alter other settings to gain proper exposure. Is this the case with these models (and other models as well) - no alteration of ISO with other settings and exposure meter viewable concurrently?

Thanks in advance.