Help: 580EX doesn't zoom with 20D

Hi,

I've just got a Canon 580EX flash for my 20D with 28-135 IS lens. It's all looking great except that the zoom indicator on the lens doesn't change automatically.

I've tried different camera modes (full auto, Av etc.) and a different lens (18-55mm EF-S kit lens) but the result is the same - the flash is reading the apperture but not the zoom level.

If I do it manually I can set zoom level on the flash.

Is it a faulty flash or am I doing something wrong.

Any advice will be appreciated!