In the tutorial there's an arsenal kit. it still has the shades. I have photoshop but how do i fill my kit with coulours without losing those shades?

use this method:
http://www.mccannas.com/pshop3/pshop24.htm

uhm.. that's paintshop

and i have photoshop5.5

its photoshop and paintshop, you should be able to do a similar task in photoshop, just look for a similar option in photoshop menu.