Here are the facts. That mobo was never designed for that high of bus speeds. Abit has released some BIOS upgrade for some of their i845 chipset mobos (although I'm not sure the BE7 is one of them). Even if there was a BIOS that supported the 800 bus CPUs, there is no guarantee that the system would be stable at 200 FSB. For the sake of the argument, let's say you luck out and can run the 800 bus CPU... dang it, there is no room for overclocking now.
My advice is if you want a 2.4C, get a mobo that was designed for it. If you don't want to give up your mobo, then get a 2.4B 533 bus CPU instead.