Problem with transforming perspective while cropping

I'm new to CS or CS2, and I was trying to do that thing where you match your crop marquee to the edges of an image that is out of perspective, then when you hit Enter to perform the crop, it automatically brings the distortion square (or rectangle). The PhotoShop help, under "Transforming perspective while cropping," says simply to "adjust cropping marquee to match the object’s edges," and it shows a point adjustment arrow being used on the corner of the crop marquee, as you would get if you were free transforming something, but all I can get the arrow to do at the corner of my crop marquee is a diagonal scaling double arrow or a rotation arrow, even if I hold down ctrl. Does anyone know what I'm doing wrong or what the trick is to adjusting the crop marquee from rectangular? Thanks.

Hold shift down while you drag the corner node in crop. I think that's what you're asking.

Look up at the Options Bar after you have made your Crop Tool selection.

You need to click the "Perspective" radio button; then you'll be able to skew those corner nodes independently.

Yes, Phosphor, that's it. Thanks. Of course, it would be really nice if the PhotoShop help were more clear in mentioning that you need to click on that first. (Hint, if anyone from Adobe is reading this!)

more clear in mentioning that you need to click on that first

There's a clue somewhere in the word "perspective" <grin>

....and there's no clue in the fact that the help topic makes no mention of the very existence of that selection box. <scowl>