There are a couple of ways to get more steam - one is to preheat a pan or skillet (not one that you care about) on the bottom rack. When you put the bread in to bake, you put a ladle-full of water into the preheated pan. It almost instantly vaporizes. You have to be careful not to burn yourself. Shut the door quickly to trap the steam.
See, the fact that there is a hard shell/crust makes me think it is a dough without much added fat (oil, eggs, butter, etc.) because all the oils in rolls usually keep the crust soft.
Sorry, I still have no idea what kind of rolls they were. I'm very intrigued, though.