To cook the lobster: Bring two inches of water to a boil over high heat, in a very large pot. Add the lobsters and hold down the lid to kill them quickly. Steam them for 12 minutes.
Remove the lobster meat from the shells, and chop it all up in half inch pieces.
Put the lobster in the bowl and add the rest of the ingredients, except for the rolls and butter. Cover and chill for two hours.
Melt the butter on medium heat on a grill pan and cook the rolls until they have grill marks.