channels help

i'm trying to use this tutorial for the "X-file" effect:

http://www.webdeveloper.com/design/...les_effect.html

and from the part that says:

"Switch to channel RGB. Select>Load Selection... choose channel "green". Now pick some nice green color as foreground color. Here, this setting is used R:0 G:255 B:0.."

i don't understand how that works, b/c you cannot edit fill with RGB selected. any ideas?

press F6 click the color tab on the swatches palette...fill in the boxes.