and for anyone stuck on drawing, adjust the white bar's width to 6 (if that wasn't common sense for you...I'm just making note of things I had to do myself)
@Betoqp:
Here's a hunch that should work...make the missile's velocity negative. (assuming it has a velocity...I started this particular tutorial but I've got some game/programming experience)
I had to totally warp mine for it to work properly...I made two movieclips next to each other in the background layer (thus not merely making the image twice as long) and had each one reset at 2110 when it finished scrolling
 "Reys Flash Tips #1"){kind=icon}
 "Shootorial #3"){kind=icon}
 "Shootorial #2"){kind=icon}
 "Shootorial #0"){kind=icon}
 "Storyteller"){kind=icon}
 "The Majesty of Colors"){kind=icon}
 "Bowja 3 - Ninja Kami"){kind=icon}
 "Morningstar"){kind=icon}
 "Use Boxmen"){kind=icon}
 "Smoking Kills"){kind=icon}
 "me and the key"){kind=icon}
 "Little Wheel"){kind=icon}
 "GemCraft chapter 0"){kind=icon}
 "Heavy Weapons"){kind=icon}