Anyone notice this mis-communication from Camera to flash.
Try this:
Set the 580EX to Manual w/ High shutter speed mode.
Set the camera, in this case a 5D, to AV mode.
Tap the release...
The shutter jumps to 1/8000th.
In the TV Mode it jumps to f/22 and blinks...
Never really use the M-mode with the flash on camera...I guess they really want you to go Manual flash and Manual on camera...