I first did this with CongreGATE.
1. You are using WordPress permalinks with mod_rewrite or a similar option.
2. You don’t have register_globals() turned on. Turn it off to ensure WordPress’s global variables don’t get removed by Kohana.
First, you need to rename the
__() function in Kohana. Say, you rename it to
__t(). You’d need to replace it everywhere it appears, which if you use an editor like Netbeans that can find usages of a function or method is pretty easy.
The next decision you need to make is whether you want to load WordPress inside Kohana or Kohana inside WordPress. I prefer the latter, which I’m documenting below.
I put the kohana directory in my theme directory.
In your functions.php file of your theme, simply
include TEMPLATEPATH . '/kohana/index.php';