I'm not sure what you're expecting. But the volume filling up as things gets written to it sounds like the right behavior.
As for block zeroing and VAAI support, those features are enabled on the array via the 'host mode options' you specify on your host groups. Below is a link to some of the popular host modes on Hitachi arrays, including zeroing support(114) and VAAI(54&63):
So check your host group if you're not getting the intended behavior, it's more likely a host mode setting that's missing.