I generally carry my BV500 vertically in the pack but its a 70l pack so not really an issue to pack around. It will fit horizontally but I have found that to be uncomfortable.
Otherwise it seems more usual for people to strap them to the top of their packs.
One trick I have seen is to pack the food in a food sack inside and carry the bear can empty strapped to the top of the pack. That way you can better balance the weight in your pack and you will have the can to use when you get to camp. You must be careful to not leave your pack unattended during the day without first moving the food to the can.
I doubt you will find carrying something that bulky stapped below your pack to be a comfortable arrangement.