I recently bottled my choclate coffee stout,
I started with the coopers irish stout kit (the green can, not the white one). Boiled 1kg of DME and mixed with the can (I didn't want to boil the can for fear of driving off the hopping).
I didn't add any coffee as I found the kit to have some very significant smokey coffee notes when it went into secondary. For choclate I made a liquoer of 1 oz good vodka and several ounces cocoa. let sit for a week and then mixed it in at time of bottling. Make sure the liquor is liquidey though, mine was jellyish (too viscous) and I had problems dissolving it.
Three weeks on, and it's starting to come together nicely but still needs aging. It's certainly drinkable now but the flavours need to gel more to be really good imho.
also if doing a second batch I think I'd add the coffee after all, the flavor is there but you have to activly pick it out, I personally would prefer if it's a little more upfront
Hope that helps!