Hey Owl...I think I read someplace that you're useing GIMP? Well, I did a tutorial on 3D rivets at M4T a ways back for GIMP.
Here's the link... http://www.mission4today.com/index.php? ... ow&kid=508
Even though I'm using a 109 temp as an example, this will work for all skins/templates...just remember to adjust the opacity for a "smooth" final appearance.
I've moved on from GIMP to Photoshop since then, but like Cipher says...simmerspaintshop is a great place for tuts on skinning.