No mate, I appologize, I don't think i've explained it the best I could.
With my 400D, you turned the camera on and doosh, the LCD was all lit up white, all the ISO & other details etc showing. It was always on, unless you had your eye to the viewfinder, or you had pressed 'disp' and turned it off.
With the 40D (or with mine), when you turn the camera on, everything else comes on (including the LCD on the top), but the main LCD at the back remains off. You can take photos, and it still stays off.
You put it in LiveView, and it comes on. You review images, it comes on. But other than that, it just stays off. Unless, that is, you click on a menu ie. picture set (landscape, portrait, monochrome etc), when you come back OUT of that menu, the screens all lit up as you'd expect.
You take a photo, review it, delete it or whatever, and go to shoot another one, and the screens gone to being off again. You go back into the same menu, come back out and it's on again.
That give a clearer description dude?