[Perfectlap]

good idea with the 3M fine cut and rubbing compound.
I think they sell it at Pepboys or autozone over here on the east coast.
Get some painter's blue tape from Home Despot and tape on either side
of the scratch. clean with dawn maybe even clay it. Get it clean clean clean.
Try the rubbing compound and fine cut.
Best to do this at night under some flood lights or pick up a fluroscent lamp.

if this doesn't work you might have to get some of that 2000 grit sand paper
and try the wet sanding Stryke refered to.
I doubt a scratch that long (sounds like vandalism?) was applied with too much pressure.
Mid America Motorworks sells parking lot door protectors which help avoid accidental scratches.
I always park about a block away from any store or movie theater etc.