Updating iOS without activating iPhone

I manage phones for a university and do alot of iPhone upgrades. One issue I often see if when the new phone will need a software update before I can restore from the iCloud backup. This was never an issue with the old 3G phones, since they wouldn't want to self-activate when turning them on. I tried iTunes as well and it also says the phone needs to be activated before it can be updated. Has anyone figured out a way to do this, or if it's possible? This process add up to 30 minutes to the process of me upgrading our users phones. I'd like to get them in and out as soon as possible, and figure if I can update the phones iOS first, it would be a nice time saver.