I'm using PsP 8 and created a custom line with a "rivit" every 5th pixel. This way, I can draw it as a vector line and be able to move, resize, or rotate it later.
I'll create 2 layers, one for white and the other for black and work with the positioning of the two till I get the effect I like, then change the opacity to match the tone of the plane.
The one flaw I've found with this is that most of the rivets will be similar. I like the effect nopoop has achieved with his rivets, as a couple will be brighter then the others, giving the effect that the paint was chipped off some directly next to others.
I'm giong to play around with changing my rivet layers to a raster layer after they are laid out, then i'll be able to adjust the brightness of a couple rivets to get the same effect.