I had the same thing happen on launch day. Got in line at 2am, the corporate store wouldn't let me transfer my upgrade from my iPad line - I guess only the customer service number can do it or you can do it yourself online - so I had to use the new line of service I was adding to get the iPhone5 (which I was just throwing my old iPhone on for someone). The store activated it then tried to transfer it and said whoops sorry you have to call customer support and they can do it. Got home at 8:30am and called and at that time they had no clue about the 24 hour waiting period. By the time I got the phone active on the correct line it was 10am Sunday morning, only 2 full days later.
Haven't heard there's a work around yet, hopefully I'm wrong. My experience was on Verizon.