The screen saver screen does come up but as you noted it is hard to see because the backlight timer turns the backlight off before the screensaver takes affect. Hit any key. The backlight will come on, you will briefly see the screensaver before the wallpaper displays. I have never found a way around this but I am not sure I want or need to. Keeping the backlight on longer will only kill the battery. If you really want to display an image set it up as wallpaper not a screensaver.
Actually, mine was black--not hard to see, but black, when the backlight went off. But...it's looking like it was a problem with the phone. I looked at the display models, and the screensaver is visible (though dark) on them. Mine was not visible at all, although you would see it flash briefly when you woke up the phone. Strange, because the screen worked ok otherwise, but losing the backlight killed ALL visibility.
The phone had other issues too (the outside display kept whacking out). When the tech went to load new software, the whole thing died, so they're sending me a new one which will hopefully correct the whole issue.