Double-barreled Musket and Vital Strike

[Sober Caydenite]

How do these items interact? A double-barreled musket lets you make two shots at -4 as a single attack, while Vital Strike grants an extra weapon die with the attack action. Pulling both triggers, would damage be 2d12/2d12, 2d12/1d12, or does Vital Strike create a limit of a single 2d12 shot?

[8 Red Wizards]

I don't know I'm just throwing out my first opinion and see where it goes. I think of the vital strike as precision-based damage so it would only apply to the first bullet damage roll and the second would just be rolled normal. Although I'll be watching this post to see what other people think, because this sounds interesting.