Exposure lock on 7D

Can one of you gurus help me? I've recently bought a 7D and, coming from a 40D, most of the controls are familiar - including the exposure lock button on the back ( the * button). However, on the 7D (at least, on my one) it doesn't work. My understanding is that you focus on your subject, then press the * button and exposure is locked. Yes? My understanding also is that this is the default setting. Yes?

As mentioned, the exposure lock button on my camera doesn't work - is this a fault or am i doing something wrong? Thanks for your help.

In P, Tv and Av modes, yes, it should cause the exposure to lock.

The C.Fn IV-1 controls customization of the camera. You can check there that it's designated to perform the * task.

Thanks for a very speedy reply Anders. I shall check the custom function immediately.

That's exactly what it was - it was switched off in the CF (I thought 'on' was the default setting) and I couldn't find it mentioned in the manual. Thanks Anders.

* (AE lock) is the default setting for the * button, so someone has changed it.
It's another thing that the 7D is flexible enough to let you assign AE lock to AF-ON, *, trigger half-press or the M-Fn button. Even to all of them at the same time, if you for some obscure reason would like that.

Thanks again Anders. The camera went it for calibration recently, so perhaps one of the technicians changed it for some reason.