If you can do it in the oven, just literally do the same in your cooker. Same temperature and times. In truth, a Kamado should make that very easy. I am not a Pernil expert, but, when I do a pork butt in what I call 'Carnitas'-style, it is really just cooking a whole butt, in a deep pan, loaded with aromatics, and I let it render and then slow fry in it's own fat. I suspect Pernil is normally not done any different. Essentially, place panned butt into a hot cooker, turn down the temperature, let it roast in it's own fat for 4 to 5 hours. I will sometimes baste the fat over the meat several times in the last hour, once the bone wiggles, to get the top crispy too.
me: I don't drink anymore
Yelonutz: me either, but, then again, I don't drink any less