I've never really tried that braid before, and I don't know of any instructions for it online, but after some experimentation and reference to similar braids from a whip making book and this site: http://www.lbbyj.com/index.php?main_page=page&id=4 I think the braid is made like this:

from right side: under 2, over 2, under 2.
from left side: over 1, under 2, over 2, under 1.
from right side: over 2, under 2, over 2.
from left side: under 1, over 2, under 2, over 1.

These 4 steps are repeated to make the braid.

Now on that leather working website in the bracelet section it says that the 12-strand gaucho braid is a six step braid but doesn't have instructions. When I tried to make it I only used the 4 steps above, so I could be misunderstanding the exact structure of the braid, but I think the steps above produce the right results.

-Timothy Potter

Thanks guys...I found the leather braiding tutorial and thought that has to be a way to adapt the principle of 8 stranded gaucho braid to a 12 strand braid. And the stingpage tutorial shows a different explanation to a 12 strand herringbone