I've heard of players using a cheap filter over their lens or something to slow down the velocity of the BB so the impact is lessened.
Are you using an SLR or something? By the sound of it you're using a Point and Shoot Digital.
You could probably rig something up like a sheet of plexiglass in front of the camera. Although somehow you'd need to rig it up and it's kinda impractical if you're playing.
I'm thinking it would be something like this (side view):
||-----___ <--- something to attach plexiglass to camera
||....|__...| <---Camera here
||-----|__|<--- something to attach plexiglass to camera
Please ignore the periods, for some reason the spaces aren't preserved. Hope that makes sense.... If not I could probably draw it in ms paint or something and upload it.