As far as I know, no it can't download Hi-Rez files off the net. You must download to main computer and then transfer to the Sony via the wired or wireless Ethernet.
New Sony Firmware For HAPZ1ES Player
Sony has a network update available (today) for the HAPZ1ES server/player. It upgrades the firmware and adds new features. You also must update your remote software on your iPad or Tablet. It all took less than 5 minutes. Seems to be working fine, so far.