well...tha ghetto way to cut that sound is by taking electrical tape an puttin some on tha point at which it rattles...but thas tha ghetto way...its not summin id do but it should work...atleast thas wat i have been told
for starters you could sound seal tha trunk but to fix tha rattle.....does your latch have bolts?you can simply have a (big) friend sit on tha trunk while you tightn tha bolt