My advice is to just try it. You probably have a backpack. And you probably know how to do a front shoulder roll. Give it a try. See how it changes the way things work. Ask yourself whether or not you can modify it to roll better.
Safety is a concern always, no matter what type of breakfall you're performing. So approach things slowly, with little extra weight at first. Then increase the intensity when you can do so safely. If you ever feel like your back, shoulder, or neck are getting torqued or flexed in a direction they shouldn't be flexed, stop and don't try it again until you've worked out what went wrong. The backpack might change your center of gravity, which affects how you perform the breakfall. And the straps might end up riding up and strangling you or preventing your shoulder from flexing the way it needs to. You won't know until you try, which is why you need to go slow and with little weight at first.