IMO, Barrel for secondary can = problems. If you are going to do it, I would ferment in the barrel and just leave it there. I have never done it, so I can't speak fromexperience, but I would want the yeast at it's prime to be sure it takes over from any other nasties that might be growng in there. If you rack to barrel as a secondary, I would be scared about sterlization. and if you do sterilize it, remember that wood is porous and may soak in the chemicals. Maybe if you sterilize with Potassium Metabisulfite (I think thats what the wine guys do) you would be O.K.
Remember, I am just throwing out an opinion, I really don't know.
You might check out the wine making forum on the links at the top of the page. There is a guy on there named Luc who seems to know just about everything. Drop a post in there and see how it comes out.