.
...as long as there's no interference between the chain rings and the frame (on the drive side), and the chain line looks good, the difference in spacing of the two crank arms is not a big deal. Some people actually prefer a bigger "Q" (the overall space between your feet as you ride with them on the pedals). There's probably a defined spindle length for your chosen crank, and maybe Campagnolo makes a proprietary offset BB unit for it, but I think it's unlikely.

But anyway, I own and ride a number of bicycles where this spacing is different, for one reason or another. Make sure you retorque the crank arm bolts after you ride 50-100 miles.