ActiveVideo certainly flexed its muscles at the Cable Show this week with a new deal for perhaps its first major customer, US cable company CableVision, the first for its new AdCast idea ‘ effectively the same idea it always has ‘ render in the cloud, but this time applied to advertising. It says that American Express has already signed up as the first advertiser to test the new platform later this year. It was at Cablevision that ActiveVideo received the fateful lawsuit from Verizon that made its fortune. The company responded to a claim that it had abused Verizon patents, but demonstrating to a court that it was the other way around, with a $260 million court win. At the…