If the camera is static you could add a section in the script for the projectiles which says for example
if position.x < 0 then playermoveX = 1
in other words set limits to how far up, down and left/right the sprite can go and then change its movement states if it reaches those values.
Not sure why you are trying to avoid static bodies at the end of the screen though I would suggest that is the best method to be honest.