Me and my .dff shadow

[Xabachee]

http://www.gtaall.com/gta-san-andreas/h ... unter.html

This Halo 4 helicopter has a perfectly large stock helicopter, the Hunter, shadow underneath it, mocking its perfection, exhibiting its creator's lack of knowledge of the volumetric shadow option. Before I add it to my MTA server I need to remove this shadow entirely or replace it with one of no significance perhaps the RC Bandit..I can see the shadow in Zmodeler, a program with which I have some experience, and can open it in GMax, a program I have no experience with. I'd prefer to mod it in ZModeler but anytime i do MTA Server returns error that the the .dff file is invalid, and inspection tells me 500KB are missing from an 800KB file so it seems the file is broken by using ZModeler... I want to remove or replace the shadow, how? It is not a locked file